100 Years of Progress in Polar Meteorologypolarmet.osu.edu/PMG_publications/walsh_bromwich... · 100 Years of Progress in Polar Meteorology JOHN E. WALSH International Arctic Research

Chapter 21

100 Years of Progress in Polar Meteorology

JOHN E WALSH

International Arctic Research Center University of Alaska Fairbanks Fairbanks Alaska

DAVID H BROMWICH

Byrd Polar and Climate Research Center The Ohio State University Columbus Ohio

JAMES E OVERLAND

NOAA Pacific Marine Environmental Laboratory Seattle Washington

MARK C SERREZE

National Snow and Ice Data Center University of Colorado Boulder Boulder Colorado

KEVIN R WOOD

Joint Institute for the Study of the Atmosphere and Oceans University of Washington Seattle Washington

ABSTRACT

The polar regions present several unique challenges to meteorology including remoteness and a harsh en-

vironment We summarize the evolution of polar meteorology in both hemispheres beginning with measure-

ments made during early expeditions and concluding with the recent decades in which polar meteorology has

been central to global challenges such as the ozone hole weather prediction and climate change Whereas the

1800s and early 1900s provided data from expeditions and only a few subarctic stations the past 100 years have

seen great advances in the observational network and corresponding understanding of the meteorology of the

polar regions For example a persistent view in the early twentieth century was of an Arctic Ocean dominated

by a permanent high pressure cell a glacial anticyclone With increased observations by the 1950s it became

apparent that while anticyclones are a common feature of theArctic circulation cyclones are frequent andmay

be found anywhere in the Arctic Technology has benefited polar meteorology through advances in in-

strumentation especially autonomously operated instruments Moreover satellite remote sensing and com-

puter models revolutionized polar meteorology We highlight the four International Polar Years and several

high-latitude field programs of recent decades We also note outstanding challenges which include un-

derstanding of the role of the Arctic in variations of midlatitude weather and climate the ability to model

surface energy exchanges over a changing Arctic Ocean assessments of ongoing and future trends in extreme

events in polar regions and the role of internal variability in multiyear-to-decadal variations of polar climate

1 Introduction

The development of polar meteorology has faced

unique challenges including the remoteness and the harsh

environments of the Arctic and Antarctic Whereas the

1800s and early 1900s provided data from expeditions and

only a few subarctic stations the past 100 years have seen

an acceleration of observations and understanding of

polar meteorology In addition to the establishment of

new observing stations technology has benefitted polar

meteorology through advances in instrumentation es-

pecially autonomously operated instrumentsMoreover

spatial coverage from satellites and computer models rev-

olutionized polar meteorology which has emerged over

the past half century as a widely recognized subdiscipline

of atmospheric and climate science In this review weCorresponding author John E Walsh jewalshalaskaedu

CHAPTER 21 WAL SH ET AL 211

DOI 101175AMSMONOGRAPHS-D-18-00031

2018 American Meteorological Society For information regarding reuse of this content and general copyright information consult the AMS CopyrightPolicy (wwwametsocorgPUBSReuseLicenses)

summarize the evolution of polar meteorology in both

hemispheres beginning with measurements made dur-

ing early expeditions and concluding with the recent

decades in which polar meteorology has been central

to global challenges such as the Antarctic ozone hole

weather prediction and climate change

2 Review of the pre-1919 period (before theestablishment of the American MeteorologicalSociety)

The development of polar meteorology in the nine-

teenth century is inextricably linked to the engines of

commerce territorial expansion and geographic explo-

ration From an American perspective these begin with

theUS South Seas Exploring Expedition (also known as

theWilkes Expedition or simply theUS Ex Ex) during

1838ndash42 (Wilkes 1845ab) followed by the lesser-known

US North Pacific Exploring and Surveying Expedition

(RinggoldndashRodgers Expedition) of 1853ndash56 (Ringgold

and Rodgers 1950 US National Archives 1964) both

US Navy expeditions TheUS Navy often with private

support contributed to the search for the missing British

expedition of Sir JohnFranklin in theArctic islands north

of Canada and to a number of other early explorations

along the west coast of Greenland These efforts added

to early knowledge of Arctic meteorology mainly by

providing observations (eg Kane 1854 Kane and Schot

1859 Tyson and Howgate 1879 Bessels 1876) for com-

parison with modern observational data and also de-

scriptions of the atmospheric (as well as ice and ocean)

phenomena they encountered Steep inversions and as-

sociated mirages ice fog sea ice ridges and leads and

floating ice islands are examples The first documented

measurements of surface-based inversions were actually

made by measuring temperatures from the lsquolsquocrowrsquos nestrsquorsquo

at 32 m above sea level on Nansenrsquos Fram expedition

(Palo et al 2017) The Army Signal Service the Coast

Survey and the Smithsonian Institution frequently sup-

ported observers supplied meteorological instruments

and provided expert data reduction and publishing as-

sistance to these endeavors (eg Abbe 1893)

The Wilkes Expedition reached Antarctica but there

were no follow-up scientific expeditions to this region

organized in the United States until the first of the Byrd

expeditions in 1928 (Riffenburgh 2006) In the Arctic

however the development of the whaling industry in the

Chukchi and Beaufort Seas beginning in 1848 the pur-

chase of Alaska from Russia in 1867 and the rise of

collaborative scientific exploration of the polar regions

as demonstrated by the landmark first International

Polar Year (IPY 1881ndash84) provided steady impetus for

exploration and research in the far north

The ill-fated 1879 expedition of the USS Jeannette

which set out to reach the North Pole by following a hy-

pothetical lsquolsquothermometric gatewayrsquorsquo through Bering Strait

to an open polar sea (Bent 1872 Hayes 1867) was perhaps

the last to be motivated in large part by speculative geo-

graphical notions about the Arctic including the possi-

bility of an ice-free polar ocean Today the Jeannette

expedition or more directly the part of its wreck that

turned up years later in Greenland is known as an in-

spiration for Fridtjof Nansenrsquos attempt to drift with the

sea ice across the North Pole in the Fram (Nansen 1898)

While expeditions like those carriedoutwith the Jeannette

and the Fram certainly pressed the frontier of discoverymdash

often at a high costmdashand produced extremely valuable

results the underlying story of scientific progress is per-

haps best revealed in the sustained even routine work to

measure describe and map the lands and oceans their

resources and the weather and climate Innovation was a

key factor from the beginning as new tools for observing

the deep sea and the upper atmosphere were constantly

being developed along with more capable ships (and

later aircraft) for operation in harsh polar conditions The

value to science of the vast archive of data that was dili-

gently collected by hundreds of people over these years is

still being realized

a Early investigations of weather and ice

The earliest sustained and systematic investigations of

the weather climate and oceanography of the Arctic by

the United States came with the Alaska Purchase (https

wwwlocgovrrprogrambibourdocsAlaskahtml) The

US Coast Survey and the Revenue Cutter Service (pre-

decessor of the US Coast Guard) began with an initial

reconnaissance in 1867 with a view toward collecting in-

formation necessary for the production of navigational

charts and for theCoast Pilot ofAlaska (USCoast Survey

1869) Starting in 1880 the Revenue Cutter ServiceCoast

Guard made annual summer cruises to the northern Be-

ring and Chukchi Seas and in the process collected a

nearly unbroken series of marine-meteorological and sea

ice observations that extends to the present day (Fig 21-1)

The US Navyrsquos Bureau of Navigation also issued

Findlayrsquos (1869)Directory for the Behringrsquos Sea and Coast

of Alaska a compendium of previously published infor-

mation about the region including a review of weather

and sea ice conditions in the Arctic recorded by earlier

explorers over the previous 100 years back to Cook and

Clerkersquos voyages in 1778 and 1779 (Beaglehole 1967)

At the same time the US Army garrisoned Sitka

(New Archangelsk) and a few other former Russian

outposts forming the beginning of the station network in

Alaska that would later be developed by the Army Signal

Service (as the first official weather agency then known as

212 METEOROLOG ICAL MONOGRAPHS VOLUME 59

the Division of Telegrams and Reports for the Benefit of

Commerce and Agriculture) A break in operations oc-

curred in 1886 and all Signal Service work in Alaska was

abandoned the following year (Henry 1898) In 1890 the

meteorological duties of the Signal Service were trans-

ferred to the US Weather Bureau newly organized as a

civilian agencywithin theUSDepartment ofAgriculture

The Weather Bureau began to rebuild the Alaska station

network in the late 1890s with coverage of the coasts of

Alaska beginning to fill in by 1920 marked by the rees-

tablishment of a station at Point Barrow (Weather Bureau

1925) initially occupied by the Signal Service for the first

IPY in 1881 The development of the station network

between 1867 and 1921 is shown in Fig 21-2 Observations

from these stations have become an important part of the

record used to understand long-term climate trendsmdashin-

sights that depend on data lsquolsquosince record-keeping beganrsquorsquo

The first thorough synthesis studies of the meteorol-

ogy and oceanography of the Pacific Arctic to be pro-

duced in the nineteenth century were made by William

Dall of the US Coast Survey These were Coast Pilot of

Alaska Appendix I Meteorology (Dall 1879) and Report

on the Currents and Temperatures of Bering Sea and the

Adjacent Waters published as Appendix 16 of the Annual

Report of the Superintendent of the US Coast and Geo-

detic Survey (Dall 1882) Both are exhaustive examinations

of the data available from earlier times especially from

Russian and British sources dating back to the 1820s and

included new observations collected by the Coast Survey

the Medical Department of the Army and the Signal Ser-

vice Information was also compiled from whaling ship

captains and other sources both published and from origi-

nal logbooks Dall assembled and published in Coast Pilot

of Alaska Appendix I Meteorology a bibliography and list

of charts containing more than 4000 titles

For Coast Pilot of Alaska Meteorology (1879) Dall

produced the first set of synoptic-scale charts of mean

annual and monthly barometric pressure for the Pacific

Arctic region which provided a reasonable character-

ization of the Aleutian low Dall (1882) notes

The most striking feature presented by the curves ofmean annual pressure is a region of depressed barometerextending fromUnimakPass toKadiak [Kodiak] Island overwhich area so far as the material permits of generalizationa mean pressure is exerted of only 2965 inches This areaof depression which I shall term the Kadiak area was first

FIG 21-1 The USCGC (Coast Guard Cutter) Bearmoored to sea ice in 1918 The Bear was initially purchased by the Navy for the Greely

Relief Expedition in 1884 (Schley 1887) and subsequently served with the Revenue Cutter ServiceCoast Guard in Alaska until 1928 then on

Admiral Byrdrsquos expeditions to Antarctica from 1933 to 1940 and finally with the Navy on the Greenland Patrol during World War II It was

decommissioned for the last time in 1944 (The photograph was provided by the Coast Guard Museum Northwest in Seattle Washington)


FIG 21-2 The meteorological station network developed by the US Army Signal Service and the Weather Bureau in Alaska 1867ndash

1921 The IPY stations at Fort Conger on Ellesmere Island and at Fort Chimo (Kuujjuaq Nunavit) are also included The IPY period is

marked by gray lines The collapse of the Signal Service network in 1887 is apparent


indicated by Mr Ferrel (1875) but from incompleteness ofdata in his possession it was located somewhat too far north

Ferrel at the time with the Coast Survey and subse-

quently with the Signal Service outlined the general cir-

culation of the atmosphere based on physical principles

(Abbe 1892) including the Coriolis force well in advance

of work by Teisserenc de Bort (1883) Exner (1913)

Walker (1923) and others Figure 21-3 shows theNorthern

Hemisphere sea level pressure and prevailing winds for

January from his analysis Dallrsquos (1879) regional map for

the same month (Fig 21-4 top panel) shows a more ac-

curate placement of theAleutian low based on station data

that were unavailable to Ferrel and it provides an example

FIG 21-3 Ferrelrsquos map in Meteorological Researches for the Use of the Coast Pilot (Ferrel 1875) lsquolsquoshowing by isobaric lines the mean

pressure of the atmosphere for January in millimeters reduced to the gravity of the parallel of 458 and by arrows the prevailing directions

of the wind for the Northern Hemispherersquorsquo Although the center of action in the Pacific (Aleutian low) is placed too far north as his

colleague Dall noted the resemblance to modern maps is unmistakable (see eg Hurrell et al 2003 their Figs 1 and 2)


of the characteristic westndasheast split of the Aleutian low

Simultaneous international observations supported this

interpretation (egBulletin of InternationalMeteorological

Observations 1875ndash87 from the US Army Signal Office)

It is now understood that in winter the positions of the one

versus two centers of the Aleutian low are more important

with respect to influence on the Bering Sea environment

than its central pressure (eg Rodionov et al 2005)

Dall also documented general outlines of other im-

portant features of the regional climate in the areas of

meteorology oceanography and biology These include

mean annual and monthly air temperature patterns and

prevailing winds ocean currents and sea surface tem-

peratures the summer distribution of sea ice winds and

temperatures over boreal and tundra regions (Fig 21-4

bottom panel) and associated plants and animals The

FIG 21-4 (top) Dallrsquos (1879) regional map of barometric pressure in January showing a split Aleutian low (referred to by Dall as the

Kadiak area in general with the Kamchatka area appearing in the case of split development) Dall recognized that the lack of data from

the western Aleutians left this question ambiguous but today it is seen to be the correct interpretation (eg Rodionov et al 2005)

(bottom) Dallrsquos (1879) map of summer sea surface isotherms and main ocean currents The average extent of sea ice in summer is also

shown and is generally consistent with what is known about ice distribution in the early satellite era and before (eg Danske

Meteorologiske Institut 1900ndash1939 1946ndash1956 US Hydrographic Office 1946)


oceanography of the Bering Sea is dealt with in more

detail in Dallrsquos subsequent work

In his Report on the Currents and Temperatures of Be-

ring Sea and the Adjacent Waters Dall (1882) turned his

attention to questions that are still relevant today What

ocean currents pass between the Pacific Ocean into the

Bering Sea and thence into the Arctic by way of Bering

Strait or from the Arctic to the south What are the

temperatures of these currents and what effect do they

have on the climate including the distribution of sea ice

As he did in his work on meteorology for the Coast Pilot

Dall scoured the literature (and primary sources) from

around the world for data and collected new oceano-

graphic observations as well in his role as assistant-in-

charge of the Coast Survey vessels Yukon and Humbolt

Of particular note is the hydrographic transect of the

Bering Strait completed in 1880 likely the first ever ob-

tained (Fig 21-5) In part the motivation for the transect

was to test the hypothesis that a branch of the warmKuro

Siwo (Kuroshio) passed through Bering Strait creating

a lsquolsquothermometric gatewayrsquorsquo (Bent 1872) that the USS

Jeannette would have followed into the Arctic At the

same time the USRC (Revenue Cutter) Corwin was

searching the area around Wrangel Island for signs of the

missing ship last seen the previous September in the ice

near Herald Island (Hooper 1881) Unbeknownst to both

Dall and Captain Hooper of the Corwin Commander De

Long and the officers of the Jeannette had already ex-

ploded two of the prevailing myths that inspired their

expedition there was no such thing as a thermometric

gateway andWrangel Land was an island and not a large

landmass extending across the Arctic (De Long 1884)

Dallrsquos hydrographic transect combined with the gen-

eral survey of the region yielded a number of particular

insights He found that the current through the Bering

Strait is mainly to the north although reversible by the

wind and that the northward flow is around 1 ft s21mdash

corresponding to a total flow of 42289425 ft3 s21 (12 Sv

1 Sv [ 106 m3 s21) which corresponds well to modern

measurements (eg Woodgate et al 2005) The tempera-

ture structure resolved by theYukon transect in September

shows the warm Alaska Coastal Current (ACC) on the

FIG 21-5 (top)Map of the Bering Strait region showing surface isotherms and sea ice observed by the US Coast Survey schoonerYukon

in AugustSeptember 1880 and (bottom) the hydrographic section obtained on 5 September 1880 (Dall 1882)


eastern side of the strait and the cold Siberian Coastal

Current (Weingartner et al 1999) on the western side The

presence of sea ice at East Cape and southward seems

unusual when compared with recent data but this was

once a common occurrence (eg Danske Meteorologiske

Institut 1900ndash1939 1946ndash1956)Otherwise the temperature

range found by Dall is fairly typical As to the source of

ocean heat present in the region Dall observed that it was

primarily due to local solar radiation rather than to heat

transported into the area from the Pacific Ocean as sug-

gested by Bent (1872) a result consistent with the recent

findings by Timmermans et al (2018)

b The first International Polar Year

The first IPY is notable as the first attempt to extend

a wide meteorological network into the Arctic and

to collect simultaneous observations with similar well-

calibrated instruments and methods The first IPY was

inspired by the Austro-Hungarian naval officer and sci-

entist Karl Weyprecht (Wood and Overland 2006) The

idea for a coordinated international expedition arose from

his experience as co-commander of the Austro-Hungarian

Polar Expedition of 1872ndash74 After returning home he

reflected on the value of the thousands of meteorological

measurements made during the expedition and noted

But whatever interest all these observations may possessthey do not possess that scientific value even supported bya long column of figures which under other circumstancesmight have been the case They only furnish us with apicture of the extreme effects of the forces of Nature in theArctic regions but they leave us completely in the darkwith respect to their causes (Weyprecht 1875)

To answer that question he understood that large-scale

synchronous data collection was required just as it is now

Weyprechtrsquos address to a meeting of German naturalists

and physicians in 1875 included an enduring assessment

lsquolsquoThe entire meteorology of our day rests upon compari-

son All the successes of which it can boastmdashthe laws of

storms the theories of windsmdashare the result of synchro-

nous observationsrsquorsquo (Wood and Overland 2006)

The Second International Meteorological Congress

held inRome in 1879 supportedWeyprechtrsquos conception

of a coordinated international polar research effort and

established a commission to put it into effect It was to be

as Abbe (1893) described it lsquolsquoa simultaneous invasion of

the polar regions from all sidesrsquorsquo International partici-

pation was invited and in due course 11 nations estab-

lished 14 polar research stations 12 in the Arctic and two

in the subantarctic A number of auxiliary stations were

also established including several in Alaska Participa-

tion by the United States was the responsibility of the

Army Signal Service which established two stations one

at Lady Franklin Bay Ellesmere Island and another at

Point Barrow Alaska Lieutenant Adolphus W Greely

(an early member of the American Meteorological So-

ciety) took command of the former expedition and

Lieutenant Patrick Henry Ray commanded the latter

The results of the first IPY were mixed Lieutenant

Greelyrsquos expedition to Lady Franklin Bay was marred

by the loss of all but seven members to deprivation and

other causes Abbe (1893) stated that

the large volumes and results of the two Signal Service in-ternational polar stations as well as the work of the Polarisand Florence expeditions have contributed not a little toadvance our knowledge of the immense country lying to thenorth of the United States in fact the great importance ofthis work becomes more and more evident as other gov-ernments publish their own contributions to this year ofcooperative research and thus enable us to take a compre-hensive survey of the atmospheric conditions at that time

The full publication of the synchronous observations

unfortunately took 25 yearsmdashit was not completed until

1910 and the data were never analyzed all together as

Weyprecht had envisioned

The meteorological observations of the first IPY were

recently transcribed digitized and assimilated by modern

retrospective analysis (reanalysis) systems (eg Compo

et al 2011) and in this sense have finally fulfilled their in-

tended purpose (Wood and Overland 2006) The greater

legacy of the first IPY may be that its successful demon-

stration of international collaboration in polar science

carried on to three subsequent iterations the second IPY

of 1932ndash33 the International Geophysical Year (or third

IPY) of 1957ndash58 (IGY) and the recent IPY of 2007ndash09

c Arctic work of the Weather Bureau

The Alaska Section of the Weather Bureau was offi-

cially started in 1898 with the establishment of the Climate

and Crop Service and set up of a first-class weather station

at Sitka under the direction ofHLBall (Ball 1898) From

the end of the Signal Service years until the 1920s much of

the meteorological data for the region was collected by

volunteer observers Aside from the Sitka station 10 new

subsidiary stations were also expected to be operated by

volunteers Henry (1898) also noted lsquolsquoIt is hoped that

those to whom instruments have been issued from time to

time in previous years will also revive their interests and

report to [Ball]rsquorsquo Of 18 volunteer stations listed by Henry

that were issued instruments by the Weather Bureau the

most successful were located at Coal Harbor (1889ndash1911)

and Killisnoo (1881ndash1910) Other efforts were not as suc-

cessful Instruments sent to observers in the Northwest

Territories (Canada) were seized and in another case the

observer a missionary was murdered and the records


were lost Further development by theWeather Bureau in

Alaska in the early twentieth century was spurred by

economic development around the gold rush and the es-

tablishment of radio and cable communications (Jessup

2007) as well as the increased need for aviation weather

services beginning in the 1920s (see Encyclopedia Arctica

1947ndash51 httpscollectionsdartmoutheduarctica-beta)

The Weather Bureaursquos further contributions to polar

meteorology followed a similar pattern as in previous

years although on very small scale Between 1893 and

1902 Evelyn Briggs Baldwin aWeather Bureau observer

took part in three privately supported Arctic adventures

Pearyrsquos North Greenland Expedition in 1893ndash94 the

SecondWellmanExpedition to Franz Josef Land in 1898ndash

99 and the BaldwinndashZiegler Arctic Expedition 1900ndash02

Thiswould be the only polar activity directly related to the

Weather Bureau until the 1920s (Encyclopedia Arctica


d Early Antarctic observations

While efforts by the United States were focused on

the Arctic important work in the Antarctic was being

carried out especially by other nations Major meteo-

rological studies in Antarctica commenced with two

historical expeditions The first was in conjunction with

Robert F Scottrsquos attempt (1910ndash13) to be the first to

reach the South (geographic) Pole Scottrsquos Party peri-

shed in 1912 on the Ross Ice Shelf after having arrived at

the Pole 1 month after Roald Amundsen The role

played by weather in this tragedy remains controversial

to this day (Solomon 2001 Fogt et al 2017) Detailed

meteorological observations were collected during

1911ndash12 at the base location of Cape Evans on Ross

Island by George C Simpson who later became Di-

rector General of theUnited KingdomrsquosMeteorological

Office The reporting and analysis of the observations

were delayed byWorldWar I but appeared in a series of

volumes published in India (Simpson 1919 1921 1923)

Important was that the analysis suggested the origin of

lsquolsquopressure wavesrsquorsquo in West Antarctica (Loewe 1967)

which became a prime motivation for the establishment

of Byrd Station (808S 1208W) during the IGY (1957)

Although the observations have not been continuous

the early observations from the Byrd Station location

have enabled recent studies to demonstrate large annual

temperature increases since the IGY 228 6 138C from

1958 to 2010 (Bromwich et al 2013 2014)

The second expedition of major meteorological im-

portance was led by Douglas Mawson (the Australasian

Antarctic Expedition 1911ndash14) whose experiences were

outlined in a well-known book entitled The Home of the

Blizzard (Mawson 1915) In an ironic twist of events

the party came ashore at Cape Denison (678S 14278E)

because there was open water right to the coast providing

easy access for their ship The meteorological records

from 1912ndash13 revealed the most intense sustained wind

regime on Earth (Madigan 1929) The anemometer was

recalibrated because of doubts about the extreme condi-

tions experienced and it now appears that the revision

was overly conservative The uncorrected records reveal

an annual average wind speed of 22 m s21 with over 60

of all hourly wind speed reports falling in the range of 15ndash

30 m s21 (Parish and Walker 2006) The easy summer ac-

cess to the coast was caused by the intense katabatic winds

blowing the sea ice offshore to create coastal polynyas

(MoralesMaqueda et al 2004) and therefore choosing this

location turned out to be an unfortunate choice in retro-

spect A similar sequence of extreme katabatic wind events

was experienced in 1912 by a satellite party of the Scott

Antarctic Expedition at Terra Nova Bay (758S 1658E)(Bromwich and Kurtz 1982 Bromwich et al 1993)

e A modern renaissance in historical climatology

The advent of sparse-input reanalysis and reanalysis-

forcedmodeling and reconstruction techniques in recent

years has brought new interest in data that were col-

lected in the past but never integrated into modern

large-scale datasets [eg the International Compre-

hensive OceanndashAtmosphere Data Set (ICOADS) the

International Surface Pressure Databank (ISPD)] A

surprisingly large amount of marine-meteorological and

sea ice data collected in the polar regions by the US

Navy Revenue Cutter ServiceCoast Guard and other

federal vessels since the 1880s has never been extracted

from primary sources and compiled This deficit how-

ever is steadily being reduced through collaborative

data recovery projects organized under the Atmospheric

Circulation Reconstructions over the Earth (ACRE) ini-

tiative (Allan et al 2011) and with support from citizen-

scientists participating in Old Weather (httpwww

oldweatherorg) and similar projects (Freeman et al 2016)

Of particular note in this regard are the sea ice ob-

servations collected in the nineteenth and early twenti-

eth century Some of these data were used in a few early

studies (eg Page 1900 Simpson 1890) and from 1900

to 1939 as occasional contributions to the Danish Me-

teorological Institutersquos annual publication State of the

Ice in Arctic Seas (Danske Meteorologiske Institut 1900ndash

1939 1946ndash1956) This publication remains a primary

source of sea ice data for the period in modern datasets for

example the Hadley Centrersquos Sea Ice and Sea Surface

Temperature Dataset version 2 (Titchner and Rayner

2014 Walsh and Chapman 2001) and reanalyses that as-

similate ice information [eg the European Centre for

Medium-Range Weather Forecasts (ECMWF) twentieth

century reanalysis (ERA-20C) Poli et al 2016] Reanalyses


require a good characterization of the ice edge to establish

appropriate boundary conditions Moreover more com-

plete recovery of available ice observations provides an

invaluable baseline reference to understand the dramatic

loss of sea ice taking place in the Arctic today Ice obser-

vations from whaling ships for the period 1850ndash1913 have

been extracted (Bockstoce and Botkin 1983 Mahoney

et al 2011) and compiled into a sea ice dataset the His-

torical Sea IceAtlas (Walsh et al 2016) However the data-

rich federal logbooks have only recently been addressed

comprehensively by Old Weather citizen-scientists and

applied in current research (Schweiger et al 2018 manu-

script submitted to J Geophys Res Oceans) Thus thou-

sands of sea ice observations frommore than a century ago

have been gleaned from the logbooks of the Bear Corwin

Thetis Northland and other federal vessels and are being

put to new uses that were unimaginable to the officers who

originally recorded them (Fig 21-6)

3 From 1919 to the 1940s

Systematic aircraft-based observations of the Arctic

began in 1929 when the Soviet Polar Aircraft Fleet was

created (Polyakov et al 2003) The 1920s also saw reports

of a loss of sea ice in the subpolar North Atlantic Ocean

together with early conjectures that reduced sea ice cov-

erage should contribute to changes in cyclone activity

(Wiese 1924) In a report that would not have been out of

place in the early 2000s the American consul in Bergen

Norway provided the following report to the US State

Department in October of 1922

The Arctic seems to be warming up Reports from fish-ermen seal hunters and explorers who sail the seas aroundSpitsbergen and the eastern Arctic all point to a radicalchange in climate conditions and hitherto unheard-of hightemperatures in that part of the earthrsquos surface Theoceanographic observations have however been evenmore interesting Ice conditions were exceptional In factso little ice has never before been noted The expedition allbut established a record sailing as far north as 818290 in ice-free water This is the farthest north ever reached withmodern oceanographic apparatus (Ifft 1922)

a Second International Polar Year (1932ndash33)

Increased interest in the Arctic during this period led

to the second IPY held in 1932ndash33 A major goal was to

FIG 21-6 Officers of the USRC Thetis on the Arctic cruise of 1903 (the photograph was provided by the Coast Guard Museum

Northwest)


investigate how observations in the polar regions could

improve the accuracy of weather forecasts and as a

result the safety of air and sea transport The second

IPY was also motivated in part by the recognition

that the electromagnetic processes in the polar regions

were affecting telegraph telephone and electric power

lines In addition the availability of new instruments

such as the radiosonde as well as aircraft and motorized

vehicles for sea and land transport provided new op-

portunities for measurements including below the

surface Altogether a total of 94 meteorological sta-

tions operated in the Arctic for at least part of the

second IPY (Laursen 1959) This period provided the

first systematic upper-air measurements in the Arctic

by radiosonde and pilot balloons Plans for a network

of Antarctic stations never came to fruition because of

the global financial crisis of the 1930s In the summer of

1932 the Russian icebreaker Sibriyakov completed a

transit of the Northern Sea Route from Arkhangelsk

to the Far East (Barr 1978) Although World War II

prevented the planned archival of all the data at the

Danish Meteorological Institute much of the data

eventually found its way into a world data center that

was created under an organization that eventually be-

came known as the World Meteorological Organiza-

tion (Barr and Luumldecke 2010)

b Russian North Pole stations

A major milestone of the period between the two

world wars was the Soviet Unionrsquos establishment of the

first North Pole Drifting Station (NP-1) Established on

pack ice near the North Pole in May of 1937 the ice

station drifted more than 2800 km before its abandon-

ment 9 months later This was the first of many such

stations (from NP-1 through NP-31) deployed by the

Russians prior to the breakup of the Soviet Union

A resumption of deployments in 2003 has included sta-

tions from NP-32 through NP-40 These stations occu-

pied for periods typically ranging from several seasons

to several years provided the first multiyear records of

atmospheric oceanic and sea ice variables from the

central Arctic Ocean In addition to standard surface

and upper-air (sounding) meteorological observations

at regular intervals each day the NP stations provided

surface radiation (solar longwave and spectral albedo)

measurements total ozone andUVmeasurements teth-

ered balloon measurements in the lowest 2 km and at-

mospheric composition measurements These data are

invaluable in the construction of twentieth-century cli-

matologies for atmospheric variables as well as snow and

ice thickness The NP data have also been widely used in

the validation of historical simulations of the central

Arctic Ocean by global and regional climate models (as

well as atmospheric reanalyses) Much of our early

knowledge of the surface energy budget of the central

Arctic Ocean was built on surface flux measurements

made at NP stations (eg Fletcher 1965) as was in-

formation on cloud conditions (eg Vowinckel and

Orvig 1971) and cloud radiative forcing Even after the

first stage of NP observations ended in the early 1990s

the NP measurements formed the basis for studies of

surfacendashatmosphere interactions in the Arctic Ocean

For example NP data showed that cloud-radiative

forcing is negative for two to three months in the sum-

mer with a strong dependence of the surface radiative

fluxes on cloud fraction (Walsh and Chapman 1998)

Although the second IPY targeted Arctic observa-

tions and measurements to improve forecasts the 1930s

also saw the first attempts to document and understand

understanding the warming of the Arctic during the

1920s and 1930s The Ifft (1922) report was among the

first to point to this notable climate event As shown in

Fig 21-7 the early twentieth-century Arctic warming

was followed by several decades of cooling then by the

strong warming of recent decades These variations are

apparent in the global as well as the Arctic time series of

Fig 21-7 which illustrates the tendency for variations of

global temperature to be amplified in the Arctic (section

5i) While various recent studies have placed the early

twentieth-century warming into a framework of climate

drivers several notable observational reports and di-

agnostic studies addressed the warming while it was

ongoing or shortly thereafter Scherhag (1936) noted

that warming of the North Atlantic Subarctic region was

accompanied by a retreat of sea ice that was consistent

with anomalous wind forcing in the region A role of the

FIG 21-7 Time series of annual (OctoberndashSeptember) air tem-

perature anomaly averaged over 608ndash908N (blue curve) and the

globe (red curve) Anomalies are relative to corresponding means

for 1980ndash2010 Both the Arctic and the global time series are based

on surface air temperature measurements from land stations ar-

chived in the CRUTEM4 dataset (httpscrudataueaacukcru

datatemperature) [Source after Fig 1 fromOverland et al (2017)

see also ftpftpoarnoaagovarcticdocumentsArcticReportCard_

full_report2017pdf]


ocean including a shoaling of the halocline (eerily similar

to discussions of Arctic Ocean change in the past few de-

cades) was proposed byBrooks (1938) Carruthers (1941)

andManley (1944) The SecondWorldWar led to a hiatus

in the debate about the Arcticrsquos early twentieth-century

warming However interest resurfaced in the early

twenty-first century (eg Bengtsson et al 2004Wood and

Overland 2010 Yamanouchi 2011) While there is evi-

dence that internal variability played a key role in the early

twentieth-century warming (Fyfe et al 2013) there is still

debate about the precise roles of the atmospheric circu-

lation and the ocean The most recent IPCC assessment

(AR5) explicitly states lsquolsquoThere is still considerable dis-

cussion of the ultimate causes of the warm temperature

anomalies that occurred in the Arctic in the 1920s and

1930srsquorsquo (Bindoff et al 2013 p 907)

4 From the 1940s to the 1970s (the Cold Warperiod)

a The Second World War

The Second World War led to rapid expansion of

meteorological services In 1939 the focus in Canada

was to meet the growing needs of Trans-Canada Air-

lines The onset of war brought added needs especially

to support the Royal Canadian Air Force (RCAF) the

British Commonwealth Air Training Plan and the US

Army Air Force for ferrying activities over the Atlantic

Ocean and to Alaska In northern Canada the United

States assisted in establishing observing stations and

forecast offices (Thomson 1948 Thomas 1971) Starting

in 1940 after the German occupation of Denmark a

number of stations were set up along the coast of Green-

land these included weather stations in places like Thule

and Scoresbysund This action resulted from an agreement

with the Danish Ambassador of Denmark for the United

States to defend Danish colonies in Greenland In 1941

when Germany attacked the Soviet Union the Barents

Sea gained great strategic importance leading to a series

of efforts by Germany the United Kingdom and Norway

to gain control of Svalbard critically situated to pro-

vide data for forecasting weather in central Europe and

for attacking Atlantic convoys headed for Murmansk

Russia In this lsquolsquowar forweatherrsquorsquo theGermans established

several secret stations in Svalbard as well as in north-

eastern Greenland and Franz Josef Land (httpswww

spitsbergen-svalbardcom)

b Early work on Greenland

From September 1949 to August 1951 the meteorol-

ogists of the French Polar Expeditions under the di-

rection of Paul-Emile Victor carried out soundings of

wind and temperature on Greenland at Station Centrale

(7098N 4068W 2965 m elevation) (eg Bedel 1954)

The station near the location of Alfred Wegenerrsquos

lsquolsquoEismittersquorsquo (1930ndash31) was close to but downslope of

the crest of the ice sheet Analysis of profiles collected

under strong temperature inversion conditions allowed

Schwerdtfeger (1972) to infer that the sloped-inversion

pressure gradient force arising from the presence of cold

air over sloping terrain which was developed to explain

the behavior of the wind field in the high interior of

Antarctica also applied to interior Greenland indicating

that the governing dynamics were the same

c Early work on Antarctica

Following the historical Antarctic expeditions in the

early 1900s meteorological studies entered a period

with slow progress Richard E Byrd led three expedi-

tions to Little America on the eastern edge of the Ross

Ice Shelf starting with the base location to stage the first

aircraft flight over the South Pole in 1929 All of these

featured extensive meteorological programs that in-

cluded upper-air observations Perhaps the most im-

portant advance came in 1946 before the US Navy was

demobilized afterWorldWar II The 1946ndash47US Navy

Antarctic Expedition designated as Operation High-

jump (Byrd 1947) was conceived to map almost the

entire periphery of the Antarctic continent for the first

time Led by Rear Admiral Byrd it involved many navy

ships and aircraft This information and the associated

photographs helped to set the stage for establishing the

network of Antarctic coastal stations for the 18-month

(1957ndash58) IGY which marked the start of sustained

instrumental observations from Antarctica and thus the

beginning of many climatic records from this remote

continent

d Glacial anticyclones

While the need for climate and weather information

over the North Atlantic and Alaska remained critical

throughout the war the climate and weather of the cen-

tral Arctic remained understudied and data were sparse

A persistent viewwas of anArctic Ocean dominated by a

largely permanent anticyclonic cell First put forth by von

Helmholtz (1888) the idea was elaborated on by Hobbs

(1910 1926) in his lsquolsquoglacial anticyclonersquorsquo theory and

subsequently gained traction Jones (1987) notes that

charts from the US Historical Weather Map Series

prepared during the Second World War contained con-

siderable positive pressure biases over the Arctic Ocean

up to 1930 and lesser errors up to 1939 It seems that these

maps were compiled by relatively untrained analysts ex-

trapolating pressures into the data-poor central Arctic

with the preconceived notion of a high pressure cell


Hobbs maintained his lsquolsquoGreenland glacial anticyclonersquorsquo

theory (Hobbs 1945) involving a persistent high pressure

cell over the Greenland ice sheet with strong influences

on weather inmidlatitudes Although other investigations

found little support for the idea (Loewe 1936 Dorsey

1945 Matthes 1946 Matthes and Belmont 1950) the

thinking of anticyclones as dominant features of the cen-

tral Arctic Ocean persisted (eg Pettersen 1950 Rae

1951) Pettersenrsquos (1950) maps depict most of the Arctic

Ocean in both summer and winter as a lsquolsquoquiet zone of

minimum cyclonic activityrsquorsquo Such views may have been

influenced by Otto Sverdruprsquos observations during the

Maud expedition (1918ndash25) of the frequent passage of

cyclones along the fringes of the Arctic Ocean

e The growing data network

With the deployment of a series of the Soviet NP

drifting stations on the Artic sea ice US drifting sta-

tions the Ptarmigan series of aircraft overflights the

establishment of weather stations in the Canadian

Arctic and studies prompted by the IGY in 1957 the

observing network started to improve A key need was

better coverage over the Arctic Ocean The Soviet NP-2

station led by Mikhail Mikhailovich Somov (Hero of

the Soviet Union and recipient of three Orders of

Lenin) was deployed in April of 1950 and NP-3 as-

sumed duties in 1954 Starting in 1954 from one to three

NP stations began operating simultaneously each year

collecting meteorological data of all types including at-

mospheric soundings from radiosondes The United

States maintained a number of drifting stations notably

T-3 (also called Fletcherrsquos Ice Island named after Col-

onel Joseph O Fletcher who discovered it) Starting in

1952 T-3 was used as a scientific drift station and in-

cluded huts a power plant and a runway for wheeled

aircraft T-3 was a tabular iceberg that presumably broke

off from the small ice shelves along the northern coast of

Ellesmere Island The NP Stations were located variously

on ice islands (tabular icebergs) and thick floes of sea ice

Ptarmigan was a series of aircraft reconnaissance missions

conducted by theUSAir Force over the period from1950

to 1961 The missions included collecting soundings in the

lower troposphere over theArcticOcean fromdropsondes

that descended by parachute (Kahl et al 1992)

In terms of land-based stations Eureka on Ellesmere

Island then part of the Northwest Territories Canada

was established in April of 1947 Weather station Alert

on the northern end of Ellesmere Island was established

in 1950 and a military station was set up in 1958 The

station is named after the HMS Alert which wintered

near the site of the station in 1875ndash76 The community at

Resolute Bay on Cornwallis Island was created in 1953

as part of the lsquolsquohigh Arctic relocation effortsrsquorsquo This was

an effort by Canada to assert sovereignty in the high

Arctic because of the regionrsquos perceived strategic im-

portance As part of this effort the Canadian Govern-

ment forcibly relocated Inuit from northern Quebec to

Resolute (and to Grise Fiord) By 1947 Canada and the

United States had already built a weather station at

Resolute as well as an airstrip This was followed in

1949 by the establishments of a Royal Canadian Air

Force base

Another major driver of the improved observational

network in Canada was the establishment during the

1950s of the Distant Early Warning (DEW) Line

(Fig 21-8) The DEW Line was a system of radar sta-

tions installed in a line across Arctic Canada (some at

existing villages such as at Cambridge Bay in 1955)

intended to provide early warning of a Soviet bomber

attack Additional stations were built along the northern

coastline and Aleutian Islands of Alaska as well as in

Greenland Iceland and the Faroe Islands

f Evolving thought

FollowingWorldWar II two major Canadian research

groups emerged at McGill University a radar meteorol-

ogy group led by J Stewart Marshall and R H Douglas

in the Department of Physics and an Arctic meteorology

group within the Department of Geography led by F K

Hare The two groups merged in 1959 to form the De-

partment of Meteorology McGill became a dominant

force in studies of Arctic meteorology and climate during

this period By 1958 (before themerger) theMcGill Arctic

meteorology research group had already published a

number of key reports on Arctic meteorology that took

advantage of the growing observational network (eg

Wilson 1958 Hare and Orvig 1958)

However it is noteworthy that in the Soviet Union a

mature viewof the circulationover the centralArcticOcean

had emerged as early as 1945 In a remarkable accom-

plishment especially given the very trying wartime con-

ditions Dzerdzeevskii (1945) correctly concluded that

cyclone activity was common in the central Arctic Ocean

especially during summer His study took advantage of

data from the Russian drifting icebreaker Sedov the

drifting ice island NP-1 and other high Arctic stations

(Jones 1987)

Western scientists may have been unaware of this

work indeed even in 1958 the idea of a quiescent

Arctic Ocean persisted in some circles For example

the quiet central zone [of the Arctic Ocean] in summercoincides fairly closely with the permanent pack ice oftheArctic Sea Although a few frontal cyclones appear tocross it the prevailing state is one of monotonously slackand ill-defined circulation appropriate enough to what is


certainly the worldrsquos largest quasi-homogeneous surfaceOnly along the flanks does cyclonic cloud and rainfallbecome at all common (Hare and Orvig 1958 p 69)

It is clear however that by the late 1950s there was an

epiphany A series of studies emerged in rapid-fire suc-

cession that form a framework for our modern view of

the Arctic atmospheric circulation As noted by the

pioneering meteorologist Jerome Namias

the present generation of meteorologists is especially for-tunate in being able to realize earlier hopes of obtaininga reasonably accurate synoptic picture of the three-dimensional structure of the atmosphere over the entirepolar area These data have brought to light many phe-nomena of circulation and weather hardly suspected in for-mer years and thereby have been vital in the development ofscientific long-range prediction (Namias 1958 p 46)

Although long-term prediction (a topic of great in-

terest to Namias) has remained an elusive goal the new

data certainly enabled a much better definition of the

structure of the circumpolar vortex and features of the

surface circulation It quickly became clear that while

anticyclones are common and often persistent features

of the Arctic circulation especially in winter and over

land areas cyclones are also frequent and depending

on the season may be found anywhere in the Arctic

(Keegan 1958 Reed and Kunkel 1960) As a sufficient

number of soundings began to reach the 25-hPa level it

became possible to investigate stratospheric dynamics

and the McGill University group played a leading role

(eg Hare 1960ab 1961) as did the Institute of Mete-

orology at the Free University of Berlin under Richard

Scherhag (Scherhag 1960)

Interest grew about the nature of Arctic air masses

andArctic fronts Any synoptic analysis will reveal high-

latitude weather fronts and associated jet streams but

can an Arctic frontal zone separate from the polar

frontal zone be identified Some early studies that were

based on prevailing conceptual views (eg Palmeacuten 1951Palmeacuten and Newton 1969) did not include a separate

high-latitude Arctic frontal zone Nevertheless early

Canadian analysis schemes (Anderson et al 1955

Penner 1955) adopted a three-front model with the

northernmost (in any season) representing individual

Arctic fronts The Meteorological Branch of Canada

prepared routine synoptic charts showing the location of

FIG 21-8 The network of radar stations established during the 1950s and known as theDEW line (Source httpmilitarywikiacomwiki

Distant_Early_Warning_Line photograph taken by Technical Sergeant Donald L Wetterman US Air Force)


three fronts on the 850- 700- and 500-hPa levels Using

these data Barry (1967) examined the location of the

Arctic frontal zone over North America for January

April July and October Shapiro et al (1987) more

recently presented clear evidence in winter of Arctic jet

streams with tropopause folds between the lower Arctic

troposphere to the north and the higher Arctic tropo-

sphere to the south These fields are associated with

what are now known as tropopause polar vortices

(Cavallo and Hakim 2009 2010 2012)

A prominent climatological feature of the Arctic

summer is the thermal contrast between the Arctic

Ocean and the surrounding land areas There has long

been interest in the concept of a summer Arctic frontal

zone separate from frontal activity in midlatitudes

Dzerdzeevskii (1945) was the first to present evidence

for its existence Reed and Kunkel (1960) subsequently

looked at the issue in more detail They noted the exis-

tence in summer only of a band of high frontal fre-

quencies extending along the northern shores of Siberia

and Alaska and southeastward across Canada and

stated that it is lsquolsquoabundantly clear that the polar front

remains separate from and well to the south of the

Arctic frontal zonersquorsquo Bryson (1966) demonstrated that

the modal position of the summer Arctic frontal zone

over North America coincided closely with Reed and

Kunkelrsquos (1960) analysis as well as the position of the

tree line This led to a recurring notion of a vegetation

link Bryson (1966) proposed that the summer frontal

position might be important in determining the distri-

bution of forest versus tundra but other investigators

(Hare 1968 Hare and Ritchie 1972) instead argued that

the tundrandashforest boundary actually helps to control the

position of the frontal zone in summer because of con-

trasts in albedo evaporation and aerodynamic rough-

ness However it has now been clearly established that

a primary control on the summer Arctic frontal zone

is differential heating between the land and ocean

(Serreze et al 2001 Crawford and Serreze 2015) an idea

first advanced as early as 1945 by Dzerdzeevskii (1945)

Arctic frontal activity in particular the summerArctic

frontal zone remains an active research area Using an

analog approach Day and Hodges (2018) argue that

because of increasing landndashocean temperature con-

trasts the summer Arctic frontal zone will sharpen and

that Arctic cyclones are likely to become more frequent

and intense as the Arctic continues to warm However

work by Crawford and Serreze (2016) show the summer

Arctic frontal zone is not in itself a region of cyclogen-

esis but rather acts to intensify cyclones that pass

through it Based on coupled climate model simulations

Crawford and Serreze (2017) argue that the frontal zone

will remain a significant cyclone intensifier in the future

but that changes in frontal strength will be largely re-

stricted to June when earlier snowmelt sharpens landndash

ocean temperature contrasts

g NWP and climate models

By the 1940s through the work of Bjerknes Rossby

and others the physical mechanisms controlling weather

processes were fairly well understood enabling some

skill in forecasting which was critical to the wartime

effort The widely studied lsquolsquoD-dayrsquorsquo weather forecasts

are a prime example of the importance of meteorology

to the wartime effort However successful numerical

prediction had to await the advent of digital computers

The first successful effort in the United States was in

1950 when a team led by Jule Charney and John

von Neumann used the Electronic Numerical Integrator

and Computer (ENIAC) to solve the barotropic vor-

ticity equation (httpsenwikipediaorgwikiHistory_of_

numerical_weather_prediction) In the United Kingdom

the first numerical model forecast was made in 1952 Op-

erational numerical forecasting in the United States started

in 1955 and the United Kingdom followed suit in 1965

(httpswwwmetofficegovukresearchmodelling-systems

history-of-numerical-weather-prediction) That same year

Norman Phillips completed a 2-layer hemispheric quasi-

geostrophic computer model that is generally regarded as

the first atmospheric general circulation model (AGCM

Phillips 1956)

The year 1955 also marked the birth of the first con-

tinued effort under the US Weather Bureau to focus

on the development of AGCMs (Smagorinsky 1983)

Smagorinskyrsquos laboratory initially located in Suitland

Maryland moved to Washington DC and in 1968

gelled at Princeton University as the Geophysical Fluid

Dynamics Laboratory (GFDL) Syukuro Manabe who

joined Smagorinskyrsquos group in 1959 was a pioneer in

model development (Manabe et al 1965) In a seminal

paper published in 1975 it was shown that the temper-

ature response to a doubling of atmospheric carbon di-

oxide would be magnified in high latitudes as a result of

the recession of the snow and sea ice boundaries and the

thermal stability of the lower troposphere that limits

vertical mixing (Manabe and Wetherald 1975)

By the mid-1960s climate model development was

being led by several groups in addition to GFDL the

University of California Los Angeles Department of

Meteorology the Lawrence Livermore Laboratory and

the National Center for Atmospheric Research By the

1970s this had expanded to include the RAND corpo-

ration the National Aeronautics and Space Adminis-

tration (NASA) Goddard Institute for Space Sciences

and the Australian Numerical Meteorological Research

Centre The Arctic was not a primary consideration in


the development of the atmospheric component ofmodels

although credible simulations of sea ice and snow cover

were recognized as important to realistic simulations of

the albedondashtemperature feedbacks

h The International Geophysical Year (thirdInternational Polar Year)

The IGY also referred to as the third IPY took place

from July 1957 through December 1958 The IGY was an

international effort to coordinate the collection of geo-

physical data from around the world including both polar

regions It marked the beginning of a new era of scientific

discovery at a time when many innovative technologies

were appearing While Greenland and the upper atmo-

sphere were emphases of Arctic activities the IGY was a

watershed event for the Antarctic A continentwide dis-

tribution of weather stations was established (Fig 21-9)

The IGY marks the start of sustained instrumental ob-

servations from Antarctica and thus the beginning of

many climatic records from this remote continent such

as are available from theMetREADERdatabase (https

legacybasacukmetREADERdatahtml) An interna-

tional analysis center was established at the LittleAmerica

V station to produce the first surface and upper-air

weather maps for Antarctica and the Southern Ocean

(Moreland 1958) that were broadcast once a day Several

of the participants (egH vanLoon andPDAstapenko)

subsequently made major advances in Antarctic meteo-

rology The launch of the first satellites during the IGY

presaged the start of the comprehensive satellite network

that today is a foundation for modern numerical weather

prediction in high southern latitudes A symposium on

Antarctic meteorology held in Melbourne in February

1959 highlighted the coming explosion of meteorological

FIG 21-9 Locations of Antarctic stations operated during the IGY The flag at each location denotes the nation that operates the

station [Source Tom Woolley Illustration (httpswwwtomwoolleycomportfoliomap-infographics-for-the-polar-museum)Scott Po-

lar Research Institute (httpswwwspricamacukmuseumexhibitionsprevioushtml) University of Cambridge]


knowledge stimulated by the IGY One contribution was

the seminal effort of Ball (1960) who formulated a simple

set of equations describing the first order behavior of the

Antarctic surface winds OnceAntarctic terrain elevations

were determined with sufficient accuracy this system of

equations was exploited by Parish andBromwich (1987) to

derive a realistic depiction of theAntarctic katabaticwinds

and their concentration into a small number of conflu-

ence zones such as the one that sustains the lsquolsquoHome of the

Blizzardrsquorsquo at Cape Denison

Prior to the IGY seven countries claimed parts of

Antarctica with some of the claims overlapping while

eight other countries made no assertions of sovereignty

the latter included the United States which did not rec-

ognize the seven claims but reserved the right to make its

own in the future (httpswwwstategovtavctrty193967

htm) To preserve the continent for cooperative scientific

study and peaceful purposes that characterized the IGY

the Antarctic Treaty was signed at the National Academy

of Sciences in Washington DC on 1 December 1959 by

the 12 nations whose scientists had been active in and

around Antarctica during the IGY The Antarctic Treaty

set aside the issue of territorial claims but did not in-

validate them The treaty came into force in 1961 It has

now been acceded to by 53 nations and governs interna-

tional activities south of 608S The Scientific Committee

on Antarctic Research (SCAR) that was established at

the same time provides scientific advice to the Antarctic

Treaty System and has for example been a leading pro-

ponent of the Year of Polar Prediction (Jung et al 2016)

that is under way at the time of writing (section 5k)

Several efforts resulting primarily from the IGY led

to notable advances in meteorological knowledge of the

Southern Ocean and Antarctica Harry van Loon Jan

J Taljaard and colleagues were leaders in laying out the

basic characteristics of the atmospheric circulation cul-

minating in the Meteorology of the Southern Hemisphere

(Newton 1972) monograph One topic emphasized by van

Loon was the elucidation explanation and consequences

of the semiannual oscillation in atmospheric pressure and

wind so prevalent over the circumpolar ocean surround-

ingAntarctica (eg vanLoon 1967) Rusin (1964) focused

on the radiation and surface energy budget of Antarctica

primarily using observations from Russian stations

Schwerdtfeger (1970) presented a synthesis of Antarctic

climate that included detailed surface climatic descrip-

tions for 25 stations many based on a decade of obser-

vations starting from the IGY

5 1970s to the present (the modernsatellite era)

In the period since 1970 progress in polar meteorology

has greatly accelerated largely as a result of advances in

computer modeling satellite remote sensing and auton-

omous instrumentation Below we highlight these ad-

vances together with several globally significant weather

and climate challenges inwhich these advances have been

essential for scientific understanding and in at least one

case (the Antarctic ozone hole) mitigation actions

a The Global Weather Experiment The First GARPGlobal Experiment

In the early 1970s the Global Weather Experiment

initially known as the First Global Atmospheric Re-

search Program (GARP) Global Experiment (FGGE)

led to major progress in numerical weather prediction

To paraphrase Hollingsworth (1989) the primary goals

of FGGE were to describe the global behavior of the

atmosphere for one full year to greatly enhance nu-

merical weather prediction on the global scale and to

design an optimal observing system for this purpose lsquolsquoIn

practice the goal of the observational programme was

to describe the dynamics and thermodynamics of the

atmosphere with a horizontal resolution of about 500 km

for the whole year and with as good a vertical resolution

as possible Themain focus of the experiment was on the

tropics and on the Southern Hemispherersquorsquo

The resources required for the experiment were sub-

stantial For the first time there was a global constella-

tion of meteorological satellites consisting of lsquolsquofive

geostationary spacecraft and two polar orbiters In ad-

dition extensive deployments of ships aircraft with

dropsonde capability high-level and low-level super-

pressure balloons and drifting buoys in remote ocean

areas (especially in the Southern Ocean) along with

greatly enhanced rawinsonde and synoptic station cov-

erage both in space and time were implementedrsquorsquo (from

Hollingsworth 1989 with edits) ECMWF was founded

in 1975 to exploit the anticipated advances in global

numerical weather prediction up to 10 days ahead fol-

lowing from the Global Weather Experiment

b Discovery and understanding of the Antarcticozone hole

The stratospheric Antarctic ozone hole was discovered

in the mid-1980s by scientists from the British Antarctic

Survey (Farman et al 1985) by using total ozone amounts

that were derived from ground-based Dobson spectro-

photometer measurements at Halley and Argentine Is-

lands stations that started in the IGY This severe ozone

depletion was subsequently confirmed to be an Antarctic-

wide phenomenon in the austral spring by instruments on

the Nimbus-7 satellite that had been operating since 1978

(Stolarski et al 1986) until the publication of the Farman

et al paper overly conservative processing of theNimbus-

7 ozone retrievals had hidden the ozone holersquos presence


Subsequently satellite measurements have provided com-

prehensive mapping of the Antarctic ozone hole and its

rate of change Figure 21-10 shows that ozone depletion

was modest in 1979 but extreme in the 2000s Direct

measurements of the stratospheric chemistry started in

1986 with the National Ozone Experiment (NOZE) at

McMurdo Station This led to the explanation that het-

erogeneous chemical reactions involving anthropogenic

chlorofluorocarbons (CFCs) and polar stratospheric clouds

release atomic chlorine gas that catalyzes the destruction of

ozone (eg Solomon et al 1986 Douglass et al 2014) In

1987 the international Protocol on Substances that De-

plete theOzone Layer was signed inMontreal to phase out

CFC emissions Direct confirmation that the reductions in

CFC emissions have led to the recovery of the Antarctic

ozone hole was reported by Strahan and Douglass (2018)

The Antarctic ozone hole has a major impact on the tro-

pospheric circulation by strengthening the circumpolar

westerly winds over the Southern Ocean (Thompson and

Solomon 2002) and moving them poleward The varying

strength of these circumpolar westerlies known as the

southern annular mode (SAM) represents the extra-

tropical Southern Hemispherersquos dominant mode of large-

scale atmospheric variability andhasmany climatic impacts

(eg Thompson et al 2011 Wang and Cai 2013)

c The International Arctic Buoy Programme

Amajor milestone for monitoring the weather and sea

ice in the Arctic Ocean was the establishment of a

network of automatic data buoys to provide synoptic-

scale fields of sea level pressure surface air temperature

and ice motion (Thorndike and Colony 1981) From a

recommendation of the National Academies of Sciences

the Arctic Ocean Buoy Program began its deployments

of buoys on the sea ice surface in early 1979 in support of

the Global Weather Experiment (section 5a) Coordi-

nated by the University of Washington Applied Physics

Laboratoryrsquos Polar Science Center the program in 1991

became known as the International Arctic Buoy Pro-

gramme (IABP httpiabpapluwedu) with funding

provided by US agencies and various other nations As

the buoy program approaches four decades of operation

its uses have included the real-time support of operations

ingestion into reanalyses and diagnostic studies encom-

passing the time scales of weather the seasonal cycle

interannual variability and climate change

The first buoys were sheltered instruments deployed

on the ice surface to measure atmospheric pressure air

temperature and position Interrogated by satellite at

frequent (approximately hourly) intervals the atmo-

spheric measurements have always been available in

nearndashreal time for ingestion intomodels used for weather

forecasts or reanalyses Changes in a buoyrsquos location over

time enable the calculation of ice velocity With 20ndash30

buoys operating over the Arctic Ocean during much of

the IABPrsquos first few decades (Fig 21-11) more-accurate

fields of sea level pressure and ice velocity were con-

structed Such fields dating back to 1979 at daily intervals

FIG 21-10 Sequence of late-winter maps of ozone concentration (in Dobson units) illustrating the ozone holes (deep blue and purple)

during each year of the 2006ndash13 period taken from Newman et al (2014 their Fig 69) The occurrence of an ozone hole in each of these

years contrasts with (top left) 1979 during which ozone concentrations were much higher


are available from the Polar Science Center (eg

Thorndike and Colony 1981)

In the past two decades measurement capabilities of

the buoys have been expanded to include subsurface

variables such as ice and ocean temperature and salinity

Some buoys include ice mass balance (IMB) measure-

ments and an ice-tethered profiler (ITP) system The

IMB buoys consist of a series of thermistors spaced

10 cm apart from just above the sea ice down 3ndash5 m into

the ocean and acoustic pingers to measure snow depth

on sea ice and ice thickness from below in addition to

the fundamental surface air pressure and temperature to

support the IABP The ITP buoys consist of a small

surface capsule that sits atop an ice floe and supports a

plastic-jacketed wire rope tether extending through the

ice and down into the ocean ending with a weight

(intended to keep the wire vertical) A cylindrical un-

derwater apparatus mounts on the tether and cycles ver-

tically along it carrying oceanographic sensors through

the water column Water-property data are telemetered

from the ITP to shore in nearndashreal time The IABP now

maintains more than 100 buoys of varying sophistication

over the Arctic Ocean Most are placed on sea ice but

some are placed in openwater Buoys have an average life

span of 18 months In the future IABP hopes to increase

the average life span to 3ndash4 years

The data collected are used for real-time operations

and research Real-time operations include collecting

data for meteorological predictions IABP buoys have

helped to predict the trajectory of storms off the coast of

Alaska that otherwise would have been difficult to de-

termine Data collected by IABP buoys are also impor-

tant for forecasting sea ice conditions which are crucial

for coastal Alaskans for those engaged in subsistence

fishing and those who work in the coastal commercial

industry Shipping traffic in the Arctic region has in-

creased in recent years with the retreat of sea ice A

combination of sea level pressure air temperature and

sea ice motion help forecasters to predict better the

movement of Arctic Ocean sea ice

IABP buoys are also used to validate satellite prod-

ucts and complement the capabilities of satellite remote

sensing The NationalWeather Service and the National

Snow and Ice Data Center use buoy data for weather

FIG 21-11 Sample distribution (9 Jan 2011) of buoys operating as part of the IABP network Gray lines show buoy tracks over the

previous 60 days (source IABP from an earlier version of httpiabpaplwashingtonedumapshtml)


predictions and ice charting IABP data are also used for

atmospheric reanalysis studies To date more than 800

scientific papers have been written using data from the

IABP Much of the data collected supports efforts for

theWorld Climate Research Programme and theWorld

Weather Watch

Contributors to the US section of IABP include the

US Coast Guard the US Department of Energy

NASA the US Navy the National Science Foundation

(NSF) and researchers from academic institutions such

as the Woods Hole Institution the US Armyrsquos Cold

Regions Research and Engineering Laboratory and the

Polar Science Center Researchers from private and

public organizations from the United States as well as

France Norway China Canada Japan South Korea

India and Russia contribute to the IABP

d Antarctic automatic weather stations

Until 1980 direct surface and upper-air meteorolog-

ical observations were provided by nearly the same

network of staffed locations as established for the IGY

(Fig 21-9) Charles R Stearns from the University of

WisconsinndashMadison led the implementation of the

satellite-transmitting automatic weather station (AWS)

network (Lazzara et al 2012) Funded largely by the

NSF the AWS network in Antarctica now consists of

about 60 active sites maintained primarily by the Uni-

versity of Wisconsin The AWS units typically measure

pressure temperature winds and atmospheric moisture

at 2ndash3 m above the surface at intervals of a few minutes

but the variables observed continue to expand The

sensors now include acoustic depth gauges to measure

changes in the snow surface height Because the AWS

are deployed in remote and challenging locations with at

most annual maintenance visits data outages do occur

therefore data analysis requires care The AWS net-

work has expanded to more than 100 locations across

Antarctica (Fig 21-12) through sites provided by many

nations including Australia France the United King-

dom China Japan and Italy as well as the United

States Observations from AWS sites are critical input

for Antarctic numerical weather prediction global re-

analyses and innumerable weather and climate studies

e Arctic clouds

Arctic clouds and their radiative interactions have

emerged as a critical component of the climate research

agenda Clouds have a strong warming influence on the

surface during much of the year in the Arctic and a

cooling effect for a short period in the summer The

period of negative cloud radiative forcing ranges from a

few weeks in the central Arctic Ocean to several months

over the subarctic land areas (Curry et al 1993

Schweiger and Key 1994 Curry et al 1996) Much of the

early work on the radiative impacts of clouds over the

Arctic Ocean was based on the radiation measurements

and cloud observations from the Russian drifting ice

stations (Marshunova and Mishin 1994 Walsh and

Chapman 1998) Cloud radiative properties are strongly

dependent not only on their elevation as in lower lati-

tudes but also on the phase (liquid vs ice) of the cloud

particles (Shupe et al 2015)

Research on Arctic clouds accelerated during the

1990s and 2000s with several major field programs (see

the appendix) The Surface Heat Budget of the Arctic

(SHEBA) a yearlong field experiment centered on a

ship intentionally frozen into the Arctic pack ice during

1997ndash98 showed that supercooled liquid water droplets

are surprisingly frequent over the Arctic Ocean Recent

estimates have indicated that liquid water is present in

10ndash80 of Arctic clouds depending on the season

and location (Shupe et al 2011 Cesana et al 2012)

SHEBA was followed in the early 2000s by the De-

partment of Energyrsquos Atmospheric Radiation Mea-

surementNorth Slope of Alaska (ARMNSA) program

which included the deployment of a variety of in-

strumentation for measuring radiation and clouds on the

northern Alaskan coast at Barrow and more recently

Oliktok Point The ARM program targeted improve-

ments on model formulations of cloudradiative pro-

cesses as one of its key objectives Over the years since

2000 the ARM program has included a wide variety of

manned and remote-controlled airborne measurements

(McFarquhar et al 2011 Schmid et al 2016) including

the Mixed-Phase Arctic Cloud Experiment (M-PACE

Verlinde et al 2007) during whichArctic cloud particles

were sampled extensively Another notable field study

was the Arctic Summer Cloud Ocean Study (ASCOS)

which took place in 2008 and utilized the Swedish ice-

breakerOden (Tjernstrom et al 2014) ASCOS targeted

the physical and chemical processes responsible for the

formation of the low-level clouds that are pervasive over

the Arctic Ocean during summer ASCOS measure-

ments have been used to improve model simulations of

late-summer Arctic clouds (eg Hines and Bromwich

2017) Another Arctic field campaign the Indirect and

Semi-Direct Aerosol Campaign (ISDAC) focused on

the impact of aerosols on Arctic clouds (McFarquhar

et al 2011) From these various field programs it has

become apparent that atmospheric radiation is impacted

much more by clouds containing liquid water than by

ice-crystal clouds (Shupe and Intrieri 2004) While

clouds containing liquid are in nearndashradiative equilib-

riumwith the surface thin clouds composed primarily of

ice allow considerable surface-emitted longwave radia-

tion to escape to space (Stramler et al 2011)


Advances in remote sensing have also led to progress

in documenting Arctic cloud characteristics and their

radiative effects While surfacendashcloud contrast limita-

tions inherent in visible and infrared sensors hindered

early uses of satellite products in the Arctic lidar and

radar profilers on the CloudSat and CloudndashAerosol

Lidar and Infrared Pathfinder Satellite Observations

(CALIPSO) satellites have been used to obtain Arctic

cloud climatologies that differ in some ways from earlier

depictions For example Liu et al (2012) showed that

cloud frequencies derived from radar and lidar profilers

on CloudSat and CALIPSO have seasonal maxima and

minima in autumn and winter respectively Climatol-

ogies based on surface observations generally showed

maximum frequencies in summer (eg Vowinckel and

Orvig 1971) The lidar and radar profile results also

showed that about 25 of Arctic clouds are multilay-

ered CloudSat and CALIPSO products have also been

used to assess weather prediction models simulations

of clouds (Candlish et al 2013) and radiative fluxes

(Zygmuntowska et al 2012)

Despite the importance of Arctic clouds and their

composition models still have difficulty in producing the

correct Arctic cloud types (de Boer et al 2012) and for

that reason poorly represent Arctic surface energy

fluxes (Tjernstrom et al 2008 Pithan et al 2014) For

simulations of climate these deficiencies have serious

implications for surface temperatures and cryospheric

change (Persson 2012) As noted in section 6 the Arctic

surface energy budget and its relation to clouds remain

major challenges of polar meteorology and polar climate

science This realization has driven the upcoming Multi-

disciplinary Drifting Observatory for Studies of Arctic

Climate (MOSAiC) program an international Arctic drift

expedition planned for the marginal ice zone in 2019ndash20

(Shupe et al 2016 httpswwwmosaic-expeditionorg

FIG 21-12 AWSs operated inAntarctica during 2018 The symbols denote the institutions that operate each station (legend in lower right)

[Source theAntarcticMeteorological ResearchCenter of theUniversity ofWisconsinndashMadison Space Science andEngineeringCenter (http

amrcssecwisceduaws) created by Sam Batzli under NSF Grant ANT-1543305]


fileadminuser_uploadMOSAiCDocumentsMOSAiC_

Implementation_Plan_April2018pdf)

f Satellite-derived soundings of the atmosphere

Radiation emitted by Earthrsquos atmospheric gases and by

clouds is recorded by polar-orbiting satellites in the infrared

and microwave wavelengths These emissions can be used

to infer the temperature and moisture content of the broad

atmospheric layers from which they originate using emis-

sion weighting functions Profiles of atmospheric tempera-

ture and water vapor amounts from across the globe

are provided by spaceborne observations for numerical

weather prediction These profiles are especially valuable in

the polar regions where the network of rawinsonde stations

has large gaps over the polar oceans and even over land

The era of satellite sounding of the atmosphere pri-

marily started with the launch of the TIROS-N space-

craft in 1978 (httpssciencenasagovmissionstiros) for

the Global Weather Experiment It included the first

TIROS Operational Vertical Sounder (TOVS) that

consisted of the High Resolution Infrared Radiation

Sounder (HIRS) theMicrowave SoundingUnit (MSU)

and on some satellites the Stratospheric Sounding Unit

(SSU) Satellite sounding has advanced tremendously

since the 19 channel HIRS era A recent example is

the InfraredAtmospheric Sounder InterferometerndashNew

Generation (IASI-NG) sounder that has 16 920 channels

spanning the infrared from 362 to 1550 mm Designed

for temperature and humidity sounding ozone profiling

and total-column or profiles of greenhouse gases it is

planned for flight on the European MetOp series of

polar orbiters starting in the 2021 time frame (https

wwwwmo-satinfooscarinstrumentsview206)

g The fourth International Polar Year (2007ndash09)

According to Krupnik et al (2011)

the International Polar Year (IPY) of 2007ndash2008 co-sponsored by ICSU and WMO became the largest co-ordinated research program in the Earthrsquos polar regionsfollowing in the footsteps of the IGY An estimated 50000researchers local observers educators students and sup-port personnel frommore than 60 nations were involved inthe 228 international IPY projects (170 in science one indata management and 57 in education and outreach) andrelated national efforts The IPY generated intensive re-search and observations in theArctic andAntarctica over atwo-year period 1 March 2007ndash1 March 2009 with manyactivities continuing beyond that date All IPY projectsincluded partners from several nations andor from in-digenous communities and polar residentsrsquo organizations

Although meteorology was the major focus of the first

IPY (1882ndash83) the 2007ndash09 IPY was far broader in its

scientific projects and involved a large range of disciplines

spanning geophysics ecology human health social sci-

ences and the humanities This increased breadth in-

dicates that modern atmospheric science has become

multidisciplinary In many cases there was a significant

atmospheric component to IPY projects carried out in

topic areas such as ice ocean land people and others

(Krupnik et al 2011 p 137) Purely atmospheric topics

included the International Arctic Systems for Observing

the Atmosphere (IASOA) observing network radiation

measurements from Spitzbergen aerosol measurements

in the Arctic and Antarctic investigations of Antarctic

polar stratospheric clouds and associated ozone de-

pletion initiation of the regional synthesis of the physical

components of Arctic climate known as the Arctic Sys-

tem Reanalysis (section 5h) investigations of Arctic

weather phenomena and their forecastability as a prelude

to the Polar Prediction Project (section 5k) the Con-

cordiasi Project over Antarctica that featured develop-

ment of more effective assimilation of radiances from

hyperspectral infrared and microwave sounders over

snow and ice and also featured dropsondes launched re-

motely from stratospheric superpressure balloons in part

to improve numerical weather prediction and also as a

run-up to the Polar Prediction Project and investigations

of air pollutants impacting the Arctic

h Reanalyses and the polar regions

Global reanalyses provide valuable tools for investigating

climate variability and change in the data-sparse polar re-

gions for example exploring the spatial and temporal

variability of Antarctic snow accumulation (Medley et al

2013) These reanalysis datasets are produced by merging

a short-term numerical weather prediction with a wide

variety of ground-based aircraft and satellite-based ob-

servations of the atmosphere while taking into account

uncertainties in both the prediction and the observations

However there are some important issues in using rean-

alyses to investigate polar climate change Although the

data assimilation system and the forecast model do not

change artificial shiftstrends can arise because of the

changing observing system This sensitivity is heightened in

high southern latitudes because of limited direct meteoro-

logical observations prior to the Global Weather Experi-

ment in 1979 (eg Bromwich and Fogt 2004) For example

the introduction of satellite atmospheric sounding data in

late 1978 produced a jump in the Antarctic precipitation

minus evapotranspiration (P2 E) simulated by the ERA-

40 global reanalysis (eg van de Berg et al 2005) Even

during themodern satellite era (after 1978) the assimilation

of radiances from theAdvancedMicrowave SoundingUnit

(AMSU) in the late 1990s introduced a pronounced jump

into the precipitation forecast by the MERRA global re-

analysis (eg Bromwich et al 2011a)Global reanalyses are


less problematic in high northern latitudes as a result of

extensive surface and upper-air observations collected from

the land areas surrounding the Arctic Ocean As for the

Antarctic the greatest challenges arise for those variables

that are not observed but depend on the model physics for

their generationmdashnamely clouds precipitation radiative

fluxes and surface energy fluxes (Lindsay et al 2014)

A regional reanalysis for the lsquolsquogreaterrsquorsquo Arctic (pole-

ward of 408N) has been produced for 2000ndash12 to

provide a more refined tool to investigate rapid climate

change happening inArctic latitudes Two versions of the

Arctic System Reanalysis (ASR) are available at 30-km

(version 1) and 15-km (version 2) grid spacing with a high

vertical resolution (eg Bromwich et al 2018) and the

latter is being updated to the present The strengths of

this high-resolution regional reanalysis reside in its more

accurate reproduction of surface variable behavior (10-m

wind 2-m air temperature etc) and in realistically cap-

turing topographically forced winds The ASR also pro-

vides an improved depiction of cyclones relative to

coarser global reanalyses including polar lows (Smirnova

and Golubkin 2017) although approximately one-third

of the polar lows are not analyzed by the ASR For such

purposes the effective resolution of the ASR is about 7

times the 15-km resolution (Skamarock 2004)

i Arctic amplification and the recent Arctic warming

Arctic amplification which refers to the observation that

the Arctic warms and cools faster than the rest of the

Northern Hemisphere and the global mean has become a

major topic of climate research Figure 21-7 illustrates this

behavior by showing the annual values of the Arctic and

global temperatures since 1900 In recent decades the

Arctic has warmed at twice the rate of the global and

Northern Hemispheric mean temperatures Arctic ampli-

fication a long-expected Arctic response to climate warm-

ing and evident in simulations from even the earliest

generation of global climate models (eg Manabe and

Wetherald 1975) started to clearly emerge toward the end

of the twentieth century (Serreze et al 2009 Screen and

Simmonds 2010) One of the major drivers of observed

Arctic amplification is sea ice loss open water areas de-

velop earlier in spring allowing for more absorption and

storage of solar energy in the oceanmixed layer through the

summer As the sun sets in autumn and winter this stored

heat is released upward to the atmosphere This heat loss

mechanism helps to explain why the Arctic amplification

signal tends to be stronger in autumn than in summer

However it is increasingly recognized that Arctic

amplification has other causes in addition to sea ice loss

Alexeev et al (2005) for example showed that polar

amplification arises in climate models of lsquolsquoaquaplanetsrsquorsquo

(ie systemswith no sea ice or snowcover) The complexity

of the processes and feedbacks challenges observational

assessments (and indeed has motivated special field pro-

grams such as SHEBA described in the appendix and

MOSAiC) For this reason comparative evaluations of

key feedbacks involved in Arctic amplification have re-

lied largely on global climate models (eg Taylor et al

2013 Pithan and Mauritsen 2014) In the latter study the

largest contributions to Arctic amplification were found

to arise from 1) the surface albedo (snow and ice) feed-

back and 2) the different vertical structure of thewarming

in high and low latitudes (lapse-rate effect) The next

largest contribution to Arctic amplification in the climate

models is the Planck effect which arises because theArctic

is colder at the top of the atmosphere than the subtropics

and radiates less energy to space While the water vapor

feedback is positive in theArctic it actually opposesArctic

amplification in climate models (Pithan and Mauritsen

2014 their Fig 2) If relative humidity stays nearly constant

in climate models then the ClausiusndashClapeyron equation

dictates a larger increase of water vapor in the tropics than

in the polar regions thereby countering polar amplifica-

tion The net role of clouds in the models was found small

but can be large in a particular season of a particular

year The largest and only substantial negative feedback in

the models is ocean heat transport which decreases as

the Arctic warms thereby reducing the Arctic warming

The different contributions vary among the global climate

models and the range of uncertainty is especially large in

the ocean transport feedback The feedbacks associated

with clouds and atmospheric transport also have wide

ranges

Atmospheric transport has also been a key contribu-

tor to recent extreme warming events For example

during January 2016 the Arctic-wide averaged tem-

perature anomaly was 208C above the previous record

of 308C (Fig 21-13a Overland and Wang 2016 Kim

et al 2017) This event caught the publicrsquos attention with

reports of temperatures warming to near the freezing

point at the North Pole The event was caused by ad-

vection of heat and moisture into the Arctic on Atlantic

and Pacific pathways as shown by contour directions

of the 700-hPa geopotential height field for January

February 2016 (Fig 21-13b) Northward advection of

temperature and moisture also results in an increase

of downward longwave radiation further warming the

surface and reducing sea ice buildup (Cullather et al

2016 Binder et al 2017 Rinke et al 2017) A similar

event occurred in the winter 201718 (Overland and

Wang 2018) Consistent with the recent Arctic warming

and the temperaturendashalbedo feedback the Arctic has

experienced record low sea ice during multiple winters

(2015ndash18) as shown in Fig 21-14 for 2017 Arctic sea

ice has shifted from mostly multiyear thick (3 m) to


mostly thin (1 m) sea ice that formed in the previous

winter (Meier et al 2014) BothArctic temperatures and

sea ice conditions are now well beyond previous expe-

rience from the twentieth century

j Regional modeling of the polar regions

1) THE ANTARCTIC MESOSCALE PREDICTION

SYSTEM

The need for optimized numerical weather prediction

for Antarctica became apparent in 1999 when Dr Jerri

Nielsen was stranded at AmundsenndashScott South Pole

Station with a serious medical condition The key ques-

tion was When would the temperature warm up enough

for planes to land safely to evacuate her in the austral

spring No convincing forecast capability existed to

provide this information As a result the Antarctic Me-

soscale Prediction System (AMPS) started in 2000 as a

collaboration between the National Center for Atmo-

spheric Research (NCAR) and the Byrd Polar Research

Center of The Ohio State University to provide an opti-

mized forecasting capability for the US Antarctic Pro-

gram (Powers et al 2012) It featuredmuch higher spatial

resolution than existing global models physical parame-

terizations optimized for the Antarctic environment and

regional data assimilation The current configuration of

nested grids is shown in Fig 21-15 with the finest reso-

lution of 09 km around Ross Island where the extensive

US aircraft operations are focused near McMurdo Sta-

tion and an 8-km grid covering all of Antarctica Every

AMPS forecast is archived at NCAR Exploration of the

early parts of the forecast that are most accurate (after

12 h of spinup from a cold start) has led to substantial

advances in understanding of Antarctic atmospheric

processes including the surface winds (eg Nigro and

Cassano 2014) storm-generation mechanisms in the

most active cyclogenesis region in the Southern Hemi-

sphere (Bromwich et al 2011b) Antarctic precipitation

(Schlosser et al 2016) and the climate of West Antarc-

tica (Nicolas and Bromwich 2011)

2) REGIONAL CLIMATE MODELING

During the last two decades there have been substantial

efforts devoted to regional atmospheric modeling of both

polar regions The polar version of the Fifth-generation

Pennsylvania State UniversityndashNational Center for At-

mospheric Research Mesoscale Model (Polar MM5 eg

Cassano et al 2001) and its successor the polar version of

the Weather Research and Forecasting (WRF) Model

(Polar WRF eg Bromwich et al 2009) were developed

to better characterize the high-latitude environments such

as sea ice areas extensive ice sheets and tundra regions

These models have been applied to a wide variety of

weather and climate problems such a simulating the cli-

mate of the Laurentide Ice Sheet during the last glacial

period (Bromwich et al 2004) Antarctic numerical

weather prediction via AMPS [section 5j(1)] the surface

winds near Greenland (eg DuVivier and Cassano 2013)

and conditions causing summer melting of ice shelves in

the Amundsen Sea embayment of West Antarctica (Deb

et al 2018) Other major efforts have involved the Re-

gional Atmospheric Climate Model (RACMO eg Noeumll

FIG 21-13 Mean January and February 2016 spatial patterns of (a) near-surface (925 hPa) air temperature anomalies and (b) averaged

geopotential height at 700 hPa The data are from the NOAAndashNCAR reanalysis using the NOAAESRL online plotting routines [The

data and image were provided by the NOAAOARESRL Physical Sciences Division (httpswwwesrlnoaagovpsd)]


et al 2015) and the Modegravele Atmospheacuterique Reacutegional(MAR eg Fettweis et al 2017) and have focused in

particular on the mass balance of the Greenland and

Antarctic ice sheets and their contribution to sea level rise

(eg Vernon et al 2013) The Regional Arctic System

Model (RASM Cassano et al 2017) is starting to be used

to explore atmospherendashoceanndashland coupled problems in

high northern latitudes (eg DuVivier et al 2016) RASM

includes a regional ocean model that can be run at reso-

lutions of several kilometers Another regional ocean-ice

model the Pan-Arctic Ice Ocean Modeling and Assimi-

lation System (PIOMAS) has been used to simulate the

evolution of the Arctic sea ice cover including an Arctic

sea ice volume reanalysis (Schweiger et al 2011) that is

updated in nearndashreal time The global NCARCommunity

Earth System Model has been applied with a wide range

of bipolar climate change problems such as the impact

of Arctic sea ice losses on the (northern) midlatitude

atmospheric circulation (Vavrus et al 2017) and the global

climatic impacts of Arctic sea loss (Tomas et al 2016)

k Polar Prediction Project and the Year of PolarPrediction 2017ndash19

The Polar Prediction Project (PPP httpwww

polarpredictionnet) is a 10-yr initiative (2013ndash22) of

the World Weather Research Programme of the World

Meteorological Organization (Jung et al 2016) The

mission of PPP is to lsquolsquopromote cooperative international

research enabling development of improved weather and

environmental prediction services for the polar regions

(Arctic and Antarctic) on time scales from hours to sea-

sonalrsquorsquo Its core activity is the Year of Polar Prediction

(YOPP) that will take place from mid-2017 to mid-2019

YOPP focuses on improving the polar observing system

facilitating field programs implementing better represen-

tation of key polar processes in coupled and uncoupled

FIG 21-14 Evolution of Arctic sea ice area in recent years (colored lines) relative to the historical range (gray shading 1979ndash2006

average 6 1 std dev) Recent years (2015ndash18) have had the lowest winter ice areas of the post-1979 period of record [Source Nansen

Environmental and Remote Sensing Center (httpwebnerscnoWebDataarctic-roosorgobservationssmi1_ice_areapng) after a fig-

ure from the Arctic Regional Ocean Observing System (ArcticROOS httpsarctic-roosorg)]


models enhancing assimilation of polar observations

into models analyzing the predictability of sea ice on

various time scales evaluating the linkages between the

polar regions and midlatitudes developing forecast

verification approaches optimized for the polar regions

and exploring the linkage between the providers and

users of polar weather and ice information YOPP fea-

tures four special observing periods of enhanced obser-

vations and modeling namely FebruaryndashMarch 2018 in

the Arctic JulyndashSeptember 2018 in the Arctic mid-

November 2018ndashmid-February 2019 in the Antarctic

and FebruaryndashMarch 2020 in the Arctic to overlap with

MOSAiC drift across the Arctic Ocean (see section 6)

YOPP participants include the academic community and

operational forecast centers (including ECMWF and

NCEP) greatly enhancing the likelihood that YOPP

forecast improvements will be implemented to advance

regional and global numerical weather prediction for

both polar regions

6 Prioritiesopportunities for the next decade

It is apparent from the preceding review that there have

been tremendous advances in polar meteorology over the

past 100 years The study of polar weather and climate has

benefitted from advances in technology as well as a rap-

idly increasing cadre of scientists The recent warming of

the Arctic and the diminished coverage of sea ice and

snow have brought prominence to theArctic as a sentinel

of global change and the Antarcticrsquos ozone hole and its

anticipated recovery continue to make the Antarctic a

focus of monitoring and research

FIG 21-15 June 2018 nested grid configuration of AMPS The outermost grid resolution is

24 km Antarctica and the adjacent SouthernOcean are at 8 km the 27-km grid spans from the

South Pole to the Ross Sea and the 09-km innermost grid is focused on McMurdo Station A

27-km grid covers the Antarctic Peninsula (The image is provided through the courtesy of

NCAR)


Among the priorities that have emerged in polar

meteorology and climate research are the linkages

between polar and midlatitude weather and climate

Relationships between Arctic warming and extreme

weather and climate events in midlatitudes have been

suggested (Francis and Vavrus 2012 Cohen et al 2014)

but the robustness of the linkages has been questioned

and the mechanisms are unclear (Barnes and Screen

2015 Screen et al 2018) YOPP (section 5k) is an effort

to advance understanding and operational forecasting

capabilities in this regard Systematic assessments of the

impacts of polar data on forecasts in both hemispheres

can contribute to a firmer understanding of the impacts

of the polar regions on midlatitude weather and climate

Extreme events in the polar regions represent another

emerging research topic While changes in extreme

weather events in midlatitudes have been documented

especially increases of heavy precipitation events and

high-temperature occurrences comprehensive assess-

ments of changing extremes in the polar regions are

lacking Of particular interest in this regard are extreme

high-temperature events (Fig 21-7) which are favorable

for high-impact rain-on-snow events Other high-impact

events such as Arctic cyclones and their dynamical

precursors tropopause polar vortices (eg Hakim and

Canavan 2005 Cavallo and Hakim 2010) are poorly

documented and inconsistently simulated by weather

and climate models Moreover short-term sea ice vari-

ability has been linked toArctic cyclones (Simmonds and

Keay 2009 Simmonds and Rudeva 2012 Zhang et al

2013 Parkinson and Comiso 2013 Kriegsmann and

Bruumlmmer 2014) although the jury is still out on whether

Arctic cyclone activity will increase in the future On the

one hand increases in cyclone frequency andor intensity

will be favored by larger landndashsea temperature contrasts

in high latitudes during summer (Day and Hodges 2018)

on the other hand polar amplification will reduce the

overall northndashsouth baroclinicity of the midlatitudes

which are the source regions for many cyclones reaching

the Arctic during the nonsummer months

The surface energy budget of the Arcticmdashin particular

the role of polar clouds and radiationmdashcontinues to

challenge weather and climate prediction models Biases

in the surface radiative fluxes in global models are larger

than changes in those fluxes associated with changes in

sea ice cover Clouds and their radiative properties un-

doubtedly contribute to these biases Model tuning is

complicated by the ongoing transition from a multiyear

sea ice cover to a seasonal sea ice cover over the central

Arctic Ocean The upcoming MOSAiC program (Shupe

et al 2016) offers promise as a coordinated effort to im-

prove understanding and model simulation capabilities

with regard to the drivers of the surface energy budget

Finally work remains to be done in assessing and an-

ticipating the role of internal variability in polar climate

andweatherAs discussed in section 3b internal variability

has been at least partially responsible for multidecadal

temperature variations in the Arctic and most likely the

Antarctic as well The magnitude of internal variations

exceeds the changes arising from external forcing over

decadal time scales (Hodson et al 2013) anticipation of

changes over the yearly to decadal time scales relevant to

planners and decision-makers will have to contend with

this issue This challenge extends to the anticipation of

changes not only in atmospheric variables such as tem-

perature but in associated system components such as sea

ice snow cover and terrestrial surface variables

Acknowledgments The authors thank three anony-

mous reviewers for their constructive comments which

resulted in substantial improvements to the original

manuscript

APPENDIX

Significant Field Programs

a AIDJEX (1970ndash78)

The Arctic Ice Dynamics Joint Experiment (AIDJEX)

was the first major western sea ice experiment con-

structed specifically to answer emerging questions about

how sea ice moves and changes in response to the in-

fluence of the ocean and atmosphere In this respect it

was a scientific sequel to the voyages of the Jeannete and

the Fram as well as the drifting NP ice camps of the

Soviet Union AIDJEXwas also the first major scientific

effort conducted in the Arctic by US agencies [NSF

the National Oceanic and Atmospheric Administration

(NOAA) and the Office of Naval Research] since the

IGY in 1957ndash58 (Untersteiner et al 2009) Pilot studies

in 1971 and 1972 were followed by the main AIDJEX

field program from March 1975 to May 1976 The main

experiment consisted of a central camp surrounded

by three satellite camps arranged in a 150-km triangle

Surrounding these staffed camps was a polygon of eight

buoys at a distance of about 300 km from themain camp

AIDJEX was timely in that a new generation of ob-

serving technology was coming on line including satel-

lite navigation battery-powered buoys capable of

real-time transmission of position and other data via

satellite accurate temperaturendashsalinity probes for the

ocean in place of Nansen bottles quartz-oscillator ba-

rometers and laser equipment to measure ice defor-

mation over scales of several kilometers to several tens

of kilometers (Untersteiner et al 2009) That climate


models were in need of more-realistic ice dynamics

formulations added to the timeliness of AIDJEX

One unexpected result from AIDJEX was the dis-

covery that mesoscale eddies are widespread in the up-

per layers of theArctic Ocean These eddies which were

shown to be baroclinic in nature have diameters of 10ndash

20 km and are found in in the uppermost 50ndash300m of the

water column Current speeds in their high-speed cores

are as large as 50ndash60 cm s21 about 5 times that of the

surrounding water A total of 146 eddies were crossed by

the AIDJEX station array during the 14-month main

observation period

The successful use of automatic data buoys to de-

termine air stress and ice deformation paved the way for

expanded uses of buoys in the Arctic Ocean AIDJEX

led directly to establishment of the Arctic Buoy Pro-

gram in 1978 followed by the extension to the IABP in

1991 (see section 5c) Another legacy of AIDJEX

stemming from the use of sequential Landsat imagery

from themain observing period ofAIDJEX is the use of

satellite data for ice kinematic information including

deformation rates and changes in leads and ridges

Synthetic aperture radar data from satellites are now

routinely processed into kinematic sea ice data for

testing modeled ice motion and for assimilation into

model hindcasts AIDJEX model development has a

dual legacy in the state-of-the-art sea ice models in-

cluding those used in Earth system models the ice

thickness distribution and a plastic failure criterion

Both these features of sea ice models were foci of the

AIDJEX measurement program

b SHEBA (1997ndash98)

The Surface Heat Budget of the Arctic funded by

NSF and the Office of Naval Research was a field

project designed to quantify energy transfer processes

that occur between the Arctic Ocean and the overlying

atmosphere Planning for SHEBA started with a series

of workshops held in the early 1990s SHEBAwas based

on the premise that addressing climate feedbacks and

improving the ability tomodel theArctic system required

improved understanding of the surface energy budget

and atmospherendashoceanndashice interactions SHEBA was in

part driven by emerging observations that the Arctic was

in the midst of rapid change (Uttal et al 2002) Phase I of

SHEBA involved analysis of historical data preliminary

modeling studies and development of instrumentation to

be used in the field program Phase II of SHEBAmdashthe

field elementmdashgot under way on 2 October 1997 when

the Canadian Coast Guard icebreaker Des Groseilliers

came to a halt in the Beaufort Sea and was allowed to be

frozen in Thus began a yearlong drift that lasted until

11 October 1998 At any given time there were 20ndash50

researchers at Ice Station SHEBA SHEBA collected a

complete annual cycle of observations over spatial scales

from meters to tens of kilometers of albedo snow

properties melt ponds ice growth and melt radiation

fluxes turbulent heat fluxes cloud height thickness and

other properties and ocean salinity temperature and

currents Persson et al (2002) describe the atmospheric

measurements made during the SHEBA field program

SHEBA data are still being widely used today Scientific

legacies of SHEBA include the realization that super-

cooled clouds are surprisingly frequent over the Arctic

Ocean (section 5e) the recognition of the importance of

Arctic cloud microphysical parameterizations in climate

model simulations and the discovery that an elevated

temperature inversion is often associated with Arctic

clouds (Pithan et al 2014) The latter complements the

earlier discovery that surface-based temperature in-

versions are widespread in the Arctic (section 2)

c CHAMP (early 2000s)

The Community-wide Hydrologic Analysis and

Monitoring Program (CHAMP) was a program to study

Arctic hydrology and its role in global change CHAMP

had its origins in a September 2000 workshop supported

by NSF to assess the existing state-of-the-art in Arctic

systems hydrology and to identify research priorities that

could lead to improved predictive understanding of feed-

backs arising from changes to the Arctic water cycle

CHAMP was organized around three interacting compo-

nents 1) compilation of data to better enable monitoring

and historical analysis of elements of the hydrologic sys-

tem 2) field observations and focused process studies and

3) the development of models operating over multiple

temporal and spatial scales CHAMP [ultimately funded

as the Freshwater Integration (FWI)] proved to be highly

successful effort The hydrologic cycle was shown to be

intimately connected to all major processes defining the

character of the Arctic system as a whole CHAMP

therefore provided a platform for collaboration between

scientists fromdiverse disciplines (Voumlroumlsmarty et al 2002)

Among the many accomplishments of CHAMP was a

much better understanding of the stocks and fluxes that

constitute of Arctic hydrologic cycle the freshwater bud-

get of the Arctic Ocean processes leading to variability

and change in river discharge and nutrient transports

d BOREAS (1990sndash2000s)

The Boreal EcosystemndashAtmosphere Study (BOREAS)

was a large-scale international interdisciplinary experi-

ment in the boreal forests of central Canada While most

large field programs from the 1970s through the 1990s

addressed interactions of the atmosphere with sea ice and

the ocean BOREAS focused on the exchanges of


radiative energy sensible heat water carbon dioxide and

other trace gases between the boreal forest and the lower

atmosphere Key questions targeted by BOREAS in-

cluded the following What processes control the ex-

changes of gases and energy between the boreal forest and

the atmosphere How will climate change affect the for-

est How will changes in the forest affect weather and

climate The most intensive field experiments took place

in the mid-1990s although additional measurements

analysis and applications to model improvement contin-

ued into the 2000s BOREAS integrated ground tower

airborne and satellite measurements of the interactions

between the forest ecosystem and the lower atmosphere

Among the key findings was the fact that atmospheric

exchanges were affected at least as much by processes in

the soil as by processes in the trees of the boreal forest

Annual carbon exchanges were found to be sensitive to

summer temperatures and especially to the timing of

snowmelt and soil freezethaw which affect soil de-

composition by microbial activity While carbon uptake

by photosynthesis is also dependent on the timing of

snowmelt and springsummer temperatures net primary

production was found to be generally more stable than

heterotropic respiration (Hall 2001) Flux measure-

ments showed that the net ecosystem exchange of car-

bon in boreal wetlands is a small residual between the

much larger uptake and respiration rates However

sensitivities are such that a warming trend accompanied

by permafrost thaw could change the boreal forest

from a long-term carbon sink to a climatically impor-

tant carbon source (Hall 2001) BOREAS contributed

to improved parameterizations of fluxes of water

(evapotranspiration) and trace gases in climate models

BOREAS measurements of forest albedo also led to

improvements of weather forecasts by the ECMWF

model (Viterbo and Betts 1999)

e GEWEXNEESPI (2000s)

The ongoing Global Energy and Water Exchanges

Project (GEWEX) program is a coordinated suite of

activities to improve understanding of the water cycle

and its interactions with the atmosphere and the land

and ocean surfaces Within its global framework

GEWEX includes the Northern Eurasia Earth Science

Partnership Initiative (NEESPI) which addresses cli-

mate and environmental change in northern Eurasia

within the water and energy cycle framework NEESPI

targets not only the regional manifestations of change

but also the impacts of these changes on the global Earth

system Over a period of a decade beginning in the early

2000s NEESPIrsquos contributions include a wide range

of atmospheric terrestrial cryospheric and socioeco-

nomic topics the aggregate of which point to a more

rapid rate of change in northern Eurasia than in other

parts of the world Changes include an earlier spring

onset and longer warmer summers which have in-

creased the strength and duration of extreme events

(drought heavy precipitation and extreme tempera-

tures) (Groisman and Gutman 2013) The increasing

temperatures and warm season duration are associated

with decreases in river ice duration (Shiklomanov and

Lammers 2014) changes in icing events (Bulygina 2015)

permafrost thaw (Streletskiy et al 2015) and shrinkage

of Russian glaciers (Khromova et al 2014) Future

projections with climate and vegetation models point to

accelerated change in climate and land surface state

(degrading permafrost) as well as the potential for

northward biome shifts of taiga vegetation into tundra

regions (Shuman et al 2015) The impacts of such

changes on ecosystems and human activity have made

the NEESPI region a target for integrated assessment

modeling (Monier et al 2017)

f SEARCH (2010s)

The ongoing Study of Environmental Arctic Change

(SEARCH) is a coordinated effort to observe un-

derstand and guide responses to changes in the Arctic

system Motivated by the recognition that interrelated

environmental changes in the Arctic are affecting eco-

systems and living resources and are having an impact on

local and global communities and economic activities the

SEARCHprogram is supported by eight federal agencies

in the United States The NSF has overseen much of the

planning and organization The framing of SEARCH is

provided by a set of overarching science questions which

are intended to bridge research and societal response

How predictable are different aspects of the Arctic sys-

tem How can improved understanding of predictability

facilitate planning mitigation and adaptation What are

the Arctic systemrsquos tipping pointsmdashthe abrupt changes

that are most consequential for ecosystems and humans

How will the critical intersections between human and

natural systems in theArctic change over the next several

decades What are the critical linkages between the

Arctic system and the global system

Among the specific targets of the early phases of

SEARCH is improved understanding of changes in sea

ice permafrost and land ice with their implications for

global sea level The goals of SEARCH also include

analysis of the societal and policy implications of Arctic

environmental change An example of a SEARCH ac-

tivity with societal applications is the Sea Ice Outlook

which has included seasonal forecasts of summer sea ice

minima by several dozen research and operational groups

(Stroeve et al 2014 2015) The Sea Ice Outlook has

stimulated work to improve forecasts of sea ice over


monthly and longer time scales (eg Stroeve et al 2014

Guemas et al 2016) The Sea Ice Outlook has included

the Sea Ice for Walrus Outlook which targets coastal

communities inAlaska The Sea IceOutlook has evolved

into the Sea Ice Prediction Network with an expanding

suite of prediction products and a growing base of con-

tributors both nationally and internationally

REFERENCES

Abbe C 1892 Memoir of William Ferrel 1817ndash1891 Biograph-

ical Memoirs National Academy of Sciences 205ndash286

mdashmdash 1893 The meteorological work of the U S Signal Service

1870 to 1891 Chicago International Meteorological Congress

Rep (Part II) 53 pp

Alexeev V A P L Langen and J R Bates 2005 Polar ampli-

fication of surface warming on an aquaplanet in lsquolsquoghost forc-

ingrsquorsquo experiments without sea ice feedbacks Climate Dyn 24

655ndash666 httpsdoiorg101007s00382-005-0018-3

Allan R P Brohan G Compo R Stone J Luterbacher and

S Broumlnniman 2011 The International Atmospheric Circula-

tion Reconstructions over the Earth (ACRE) Initiative Bull

Amer Meteor Soc 92 1421ndash1425 httpsdoiorg101175

2011BAMS32181

Anderson R B Bolville and D E McClellan 1955 An opera-

tional frontal contour analysis model Quart J Roy Meteor

Soc 81 588ndash599 httpsdoiorg101002qj49708135008

Ball F K 1960 Winds on the ice slopes of Antarctica Antarctic

Meteorology Proceedings of the Symposium in Melbourne

1959 Pergamon 9ndash16

Ball H L 1898 Weather Bureau Service in Alaska Mon Wea

Rev 26 254 ftpftplibrarynoaagovdocslibhtdocsrescue

mwr026mwr-026-06-0254apdf

Barnes E A and J A Screen 2015 The impact of Arctic

warming on themidlatitude jet-stream Can it Has itWill it

Wiley Interdiscip Rev Climate Change 6 277ndash286 https

doiorg101002wcc337

Barr S and C Luumldecke Eds 2010 The History of the In-

ternational Polar Years (IPYs) From Pole to Pole Vol 1

Springer-Verlag 319 pp

BarrW 1978 The voyage of Sibiryakov 1932Polar Rec 19 253ndash266 httpsdoiorg101017S003224740001826X

Barry R G 1967 Seasonal location of theArctic front over North

America Geogr Bull 9 79ndash95

Beaglehole J C Ed 1967 The Voyage of the Resolution and Dis-

covery 1776ndash1880 Part 1 Journals of Captain James Cook on his

Voyages ofDiscovery Vol 3 CambridgeUniversity Press 718 pp

Bedel B 1954 Les observations meacuteteacuteorologiques de la station

Franccedilaise du Groenland conditions atmospheacuteriques en alti-

tude (Meteorological observations of the French Greenland

station atmospheric conditions at altitude) Expeacuteditions Po-laires Franccedilaises Missions Paul-Emile Victor Resultats Sci-

entifiques No N V 119 pp

Bengtsson L V A Semenov and O M Johannessen 2004 The

early twentieth-century warming in the ArcticmdashA possible

mechanism J Climate 17 4045ndash4057 httpsdoiorg1011751520-0442(2004)0174045TETWIT20CO2

Bent S 1872 Thermal Paths to the Pole An Address Delivered

before the St Louis Mercantile Library Association RP

Studley Co 40 pp

Bessels E 1876 Scientific results of the United States Arctic ex-

pedition Steamer Polaris CF Hall commanding US Navy

Rep Government Printing Office 986 pp httpsarchive

orgdetailscu31924029881095pagen5

Binder H M Boettcher C M Grams H Joos S Pfahl and

H Wernli 2017 Exceptional air mass transport and dy-

namical drivers of an extreme wintertime Arctic warm

eventGeophys Res Lett 44 12 028ndash12 036 httpsdoiorg

1010022017GL075841

Bindoff N L and Coauthors 2013 Detection and attribution of

climate change From global to regionalClimate Change 2013

The Physical Science Basis T F Stocker et al Eds Cam-

bridge University Press 867ndash952

Bockstoce J R and D B Botkin 1983 The historical status and re-

duction of thewesternArctic bowheadwhale (Balaenamysticetus)

population by the pelagic whaling industry 1848ndash1914 In-

ternational Whaling Commission Rep SC32PS16 107ndash141 pp

httpsarchiveiwcintpagesviewphpref5465ampk5536cb7240a

Bromwich D H and D D Kurtz 1982 Experiences of Scottrsquos

Northern Party Evidence for a relationship between winter

katabatic winds and the Terra Nova Bay polynya Polar Rec

21 137ndash146 httpsdoiorg101017S0032247400004514

mdashmdash and R L Fogt 2004 Strong trends in the skill of the ERA-40

and NCEPNCAR reanalyses in the high and middle latitudes

of the Southern Hemisphere 1958ndash2001 J Climate 17 4603ndash

4619 httpsdoiorg10117532411

mdashmdash T R Parish A Pellegrini C R Stearns and G A Weidner

1993 Spatial and temporal variations of the intense katabatic

winds at Terra Nova Bay Antarctica Antarctic Meteorology

and Climatology Studies Based on Automatic Weather Sta-

tions D H Bromwich and C R Stearns Eds Antarctic

Research Series Vol 61 Amer Geophys Union 47ndash68

mdashmdash E R Toracinta H Wei R J Oglesby J L Fastook and T J

Hughes 2004 Polar MM5 simulations of the winter climate of the

Laurentide IceSheet at theLGM JClimate17 3415ndash3433 https

doiorg1011751520-0442(2004)0173415PMSOTW20CO2

mdashmdash KM Hines and L-S Bai 2009 Development and testing of

Polar WRF 2 Arctic Ocean J Geophys Res 114 D08122

httpsdoiorg1010292008JD010300

mdashmdash J P Nicolas and A J Monaghan 2011a An assessment of

precipitation changes over Antarctica and the Southern Ocean

since 1989 in contemporary global reanalyses J Climate 24

4189ndash4209 httpsdoiorg1011752011JCLI40741

mdashmdashD F Steinhoff I Simmonds K Keay and R L Fogt 2011b

Climatological aspects of cyclogenesis near Adelie Land

Antarctica Tellus 63A 921ndash938 httpsdoiorg101111

j1600-0870201100537x

mdashmdash J P Nicolas A J Monaghan M A Lazzara L M Keller

G A Weidner and A B Wilson 2013 Central West Ant-

arctica among the most rapidly warming regions on Earth

Nat Geosci 6 139ndash145 httpsdoiorg101038ngeo1671

mdashmdash mdashmdash mdashmdash mdashmdash mdashmdash mdashmdash and mdashmdash 2014 Corrigendum

Central West Antarctica among the most rapidly warming

regions on Earth Nat Geosci 7 76 httpsdoiorg101038

ngeo2016

mdashmdash and Coauthors 2018 TheArctic SystemReanalysis version 2

Bull Amer Meteor Soc 99 805ndash828 httpsdoiorg101175

BAMS-D-16-02151

Brooks C E P 1938 The warming Arctic Meteor Mag 73

29ndash31

Bryson R A 1966 Air masses stream lines and the boreal forest

Geogr Bull 8 228ndash269

Bulygina O N 2015 Icing conditions over northern Eurasia in a

changing climate Environ Res Lett 10 025003 httpsdoiorg

1010881748-9326102025003


Byrd R E 1947Our navy exploresAntarcticaNatl GeogrMag

92 (4) 429ndash522

Candlish L M R L Raddatz G G Gunn M G Asplin and

D G Barber 2013 Validation of CloudSat and CALIPSOrsquos

temperature humidity cloud detection and cloud base height

over the Arctic marine cryosphere AtmosndashOcean 51 249ndash

264 httpsdoiorg101080070559002013798582

Carruthers J N 1941 Some interrelationships of meteorology

and oceanography Quart J Roy Meteor Soc 67 207ndash246

httpsdoiorg101002qj49706729102

Cassano J J J E Box D H Bromwich L Li and K Steffen

2001 Evaluation of Polar MM5 simulations of Greenlandrsquos

atmospheric circulation J Geophys Res 106 33 867ndash33 890


mdashmdash and Coauthors 2017 Development of the Regional Arctic

System Model (RASM) Near surface atmospheric climate

sensitivity J Climate 30 5729ndash5753 httpsdoiorg101175

JCLI-D-15-07751

Cavallo S M and G J Hakim 2009 Potential vorticity diagnosis

of a tropopause polar cyclone Mon Wea Rev 137 1358ndash

1371 httpsdoiorg1011752008MWR26701

mdashmdash and mdashmdash 2010 The composite structure of tropopause polar

cyclones from a mesoscale modelMon Wea Rev 138 3840ndash


mdashmdash and mdashmdash 2012 Radiative impact on tropopause polar vor-

tices over the ArcticMon Wea Rev 140 1683ndash1702 https

doiorg101175MWR-D-11-001821

Cesana G J E Kay H Chepfer J English andG de Boer 2012

Ubiquitous low-level liquid-containing Arctic clouds New obser-

vations and climate model constraints from CALIPSO-GOCCP

Geophys Res Lett 39 L20804 httpsdoiorg101029

2012GL053385

Cohen J and Coauthors 2014 Recent Arctic amplification and

extreme mid-latitude weatherNat Geosci 7 627ndash637 https

doiorg101038ngeo2234

Compo G P and Coauthors 2011 The Twentieth Century Re-

analysis ProjectQuart J Roy Meteor Soc 137 1ndash28 https

doiorg101002qj776

Crawford A and M C Serreze 2015 A new look at the Arctic

frontal zone J Climate 28 737ndash754 httpsdoiorg101175

JCLI-D-14-004471

mdashmdash and mdashmdash 2016 Does the summer Arctic frontal zone influence

Arctic Ocean cyclone intensity J Climate 29 4977ndash4993 https

doiorg101175JCLI-D-15-07551

mdashmdash and mdashmdash 2017 Projected changes in the Arctic frontal zone

and summer Arctic cyclone activity in the CESM Large En-

semble J Climate 30 9847ndash9869 httpsdoiorg101175

JCLI-D-17-02961

Cullather R I Y-K Lim L N Boisvert L Brucker J N Lee

and S M J Nowicki 2016 Analysis of the warmest Arctic

winter 2015ndash2016 Geophys Res Lett 43 10 808ndash10 816

httpsdoiorg1010022016GL071228

Curry J A E E Ebert and J L Schramm 1993 Impact of clouds

on the surface radiation balance of the Arctic Ocean Meteor

Atmos Phys 51 197ndash217 httpsdoiorg101007BF01030494

mdashmdash W B Rossow D Randall and J L Schramm 1996

Overview of Arctic cloud and radiation characteris-

tics J Climate 9 1731ndash1764 httpsdoiorg101175

1520-0442(1996)0091731OOACAR20CO2

Dall W H 1879 Appendix I Meteorology Coast Pilot of

Alaska US Coast and Geodetic Survey Rep Govern-

ment Printing Office 379ndash401 httpshdlhandlenet2027

nyp33433000204663

mdashmdash 1882 Report on the currents and temperatures of Bering

Sea and the adjacent waters US Coast and Geodetic Survey

Rep 297ndash340 ftpftplibrarynoaagovdocslibhtdocsrescue

cgs002_pdfCSC-0079PDF

Danske Meteorologiske Institut 1900ndash1939 Isforholdene i de

Arktiske Have (The state of the ice in the Arctic seas) I

Kommission Hos GEC Gad

mdashmdash 1946ndash1956 Isforholdene i de Arktiske Have (The state of the

ice in the Arctic seas) I Kommission Hos GEC Gad

Day J J and K I Hodges 2018 Growing landndashsea temperature

contrast and intensification or Arctic cyclones Geophys Res

Lett 45 httpsdoiorg1010292018GL077587

Deb P A Orr D H Bromwich J P Nicolas J Turner and J S

Hosking 2018 Summer drivers of atmospheric variability af-

fecting ice shelf thinning in the Amundsen Sea Embayment

West Antarctica Geophys Res Lett 45 4124ndash4133 https

doiorg1010292018GL077092

de Boer G W Chapman J Kay B Medeiros M D Shupe

S Vavrus and J E Walsh 2012 A characterization of the

Arctic atmosphere in CCSM4 J Climate 25 2676ndash2695

httpsdoiorg101175JCLI-D-11-002281

De Long G W 1884 The Voyage of the Jeannette The Ship and

Ice Journals of George W De Long Lieutenant-Commander

USN and Commander of the Polar Expedition of 1879ndash1881

Vols 1 and 2 Houghton Mifflin 911 pp

Dorsey H G Jr 1945 Some meteorological aspects of the

Greenland Ice Cap J Meteor 2 135ndash142 httpsdoiorg

1011751520-0469(1945)0020135SMAOTG20CO2

Douglass A P Newman and S Solomon 2014 The Antarctic

ozone hole An update Phys Today 67 42 httpsdoiorg

101063PT32449

DuVivier A K and J J Cassano 2013 Evaluation of WRF

Model resolution on simulated mesoscale winds and surface

fluxes near Greenland Mon Wea Rev 141 941ndash963 https

doiorg101175MWR-D-12-000911

mdashmdash mdashmdash A Craig J Hamman W Maslowski B Nijssen

R Osinski and A Roberts 2016 Winter atmospheric buoy-

ancy forcing and oceanic response during strong wind events

around southeasternGreenland in theRegionalArctic System

Model (RASM) for 1990ndash2010 J Climate 29 975ndash994 https


Dzerdzeevskii B L 1945 Tsirkuliatsionnye skhemy v troposfere

Tsentralnoi Arktiki (Circulation schemes for the central

Arctic troposphere) Izdatelrsquostvo Akademii Nauk 28 pp (An

English translation is available in UCLA Meteorology Dept

Scientific Report No 3 under Contract AF19(122)-228)

Exner F M 1913 Uumlber monatliche Witterunganomalien auf der

noumlrdliche Erdhaumllfte im Winter (On monthly weather anomalies

in the Northern Hemisphere in winter) Sitzungberichte der

Kaiserliche Akademie der Wissenschaften Vol 122 1165ndash1240

Farman J C B G Gardiner and J D Shanklin 1985 Large

losses of total ozone in Antarctica reveal seasonal CLOx

NOx interaction Nature 315 207ndash210 httpsdoiorg101038

315207a0

Ferrel W 1875 On the mechanics and the general motions of the

atmosphere Part I Meteorological researches for the use of

the coast pilot US Coast Survey Rep 64 pp

Fettweis X and Coauthors 2017 Reconstructions of the 1900ndash

2015 Greenland ice sheet surface mass balance using the re-

gional climate MAR model Cryosphere 11 1015ndash1033

httpsdoiorg105194tc-11-1015-2017

FindlayAG 1869Directory forBehringrsquos Sea andCoast ofAlaska

Arranged from the Directory of the Pacific Ocean Bureau of


Navigation Rep Government Printing Office 193 pp https

babelhathitrustorgcgiptid5hvd32044080604465

Fletcher J O 1965 The heat budget of the Arctic Basin and its

relation to climate RAND Corporation Rep R-444-PR 179

pp httpswwwrandorgpubsreportsR0444html

Fogt R L M E Jones S Solomon J M Jones and C A

Goergens 2017 An exceptional summer during the South

Pole race of 191112 Bull Amer Meteor Soc 98 2189ndash2199

httpsdoiorg101175BAMS-D-17-00131

Francis J A and S J Vavrus 2012 Evidence linking Arctic

amplification to extreme weather in mid-latitudes Geophys

Res Lett 39 L06801 httpsdoiorg1010292012GL051000

Freeman E and Coauthors 2016 ICOADS release 30 A major

update to the historical marine climate record Int J Climatol

37 2211ndash2232 httpsdoiorg101002joc4775

Fyfe J C K von Salzen N P Gillett V K Arora G Flato and

J R McConnell 2013 One hundred years of Arctic surface

temperature variation due to anthropogenic influenceNature

Sci Rep 3 2645 httpsdoiorg101038srep02645Groisman P Ya andGGutman Eds 2013Environmental Changes

in Siberia Regional Changes and Their Global Consequences

Springer 360 pp httpsdoiorg101007978-94-007-4569-8

Guemas V and Coauthors 2016 A review on Arctic sea-ice

predictability and prediction on seasonal to decadal time-

scales Quart J Roy Meteor Soc 142 546ndash561 httpsdoiorg

101002qj2401

Hakim G J and A K Canavan 2005 Observed cyclonendashanticyclone

tropopause asymmetries JAtmos Sci62 231ndash240 httpsdoiorg

101175JAS-33531

Hall F G 2001 Introduction to special section BOREAS III

J Geophys Res 106 33 511ndash33 516 httpsdoiorg101029

2001JD001526

Hare F K 1960a The disturbed circulation of the Arctic strato-

sphere J Meteor 17 36ndash51 httpsdoiorg1011751520-0469

(1960)0170036TDCOTA20CO2

mdashmdash 1960b The summer circulation of the Arctic stratosphere

below 30 kmQuart J Roy Meteor Soc 86 127ndash146 https

doiorg101002qj49708636802

mdashmdash 1961 The circulation of the stratosphere McGill University

Arctic Meteorology Research Group Publ 43 54 pp

mdashmdash 1968 The Arctic Quart J Roy Meteor Soc 94 439ndash459


mdashmdash and S Orvig 1958 The Arctic circulation A preliminary

view McGill University Arctic Meteorology Research Group

Publ 12 McGill University 211 pp

mdashmdash and J C Ritchie 1972 The boreal microclimates Geogr

Rev 62 333ndash365 httpsdoiorg102307213287Hayes I I 1867 The Open Polar Sea A Narrative of a Voyage of

Discovery towards the North Pole in the Schooner lsquolsquoUnited

Statesrsquorsquo Sampson Low 454 pp

Henry A J 1898 Meteorological work in Alaska Mon Wea

Rev 26 154ndash157 httpsdoiorg1011751520-0493(1898)26

[154MWIA]20CO2

Hines KM andD H Bromwich 2017 Simulation of late summer

Arctic clouds duringASCOSwith PolarWRFMonWea Rev

145 521ndash541 httpsdoiorg101175MWR-D-16-00791

Hobbs W H 1910 Characteristics of the inland ice of the Arctic

regions Proc Amer Philos Soc 49 57ndash129

mdashmdash 1926The Glacial Anticyclones The Poles of the Atmospheric

Circulation MacMillan 198 pp

mdashmdash 1945 The Greenland glacial anticyclone J Meteor 2

143ndash153 httpsdoiorg1011751520-0469(1945)0020135

TGGA20CO2

Hodson D S P E Keeley A West J Ridley E Hawkins and

H T Hewitt 2013 Identifying uncertainties in Arctic climate

change projections Climate Dyn 40 2849ndash2865 https

doiorg101007s00382-012-1512-z

Hollingsworth A 1989 The Global Weather Experimentmdash10

years on Weather 44 278ndash285 httpsdoiorg101002j1477-

86961989tb07053x

Hooper C L 1881 Report of the cruise of the US Revenue-

steamer Corwin in the Arctic Ocean US Treasury Doc 118

Government Printing Office 71 pp httpsbabelhathitrust

orgcgiptid5mdp39015059478647

Hurrell J W Y Kushnir G Ottersen and M Visbeck Eds

2003 An overview of the North Atlantic Oscillation

The North Atlantic Oscillation Climatic Significance and

Environmental ImpactGeophys Monogr Vol 134 Amer

Geophys Union 1ndash35

Ifft GN 1922 The changingArcticMonWea Rev 50 589 https

doiorg1011751520-0493(1922)50589aTCA20CO2

Jessup D E 2007 Connecting Alaska The Washington-Alaska

Military Cable and Telegraph System J Gilded Age Prog

Era 6 385ndash408 httpsdoiorg101017S1537781400002218

Jones P D 1987 The twentieth century Arctic highmdashFact or

fiction Climate Dyn 1 63ndash75 httpsdoiorg101007

BF01054476

Jung T and Coauthors 2016 Advancing polar prediction

capabilities on daily to seasonal time scales Bull Amer

Meteor Soc 97 1631ndash1647 httpsdoiorg101175

BAMS-D-14-002461

Kahl J DM C Serreze S Shiotani SM Skony andR C Schnell

1992 In situ meteorological sounding archives for Arctic stud-

ies Bull Amer Meteor Soc 73 1824ndash1830 httpsdoiorg

1011751520-0477(1992)0731824ISMSAF20CO2

Kane E K 1854 TheU SGrinnellExpedition in Search of Sir John

Franklin A Personal Narrative Harper and Brothers 552 pp

mdashmdash and C A Schot 1859 Meteorological Observations in the

Arctic Seas Made during the Second Grinnell Expedition in

Search of Sir John Franklin in 1853 1854 and 1855 at Van

Rensselaer Harbor and Other Points on the West Coast of

Greenland Smithsonian Institution 112 pp

Keegan T J 1958Arctic synoptic activity in winter JMeteor 15


ASAIW20CO2

Khromova T G Nosenko S Kutuzov A Muraviev and

L Chernova 2014 Glacier area change in northern Eurasia

Environ Res Lett 9 015003 httpsdoiorg1010881748-9326

91015003

Kim B-M and Coauthors 2017 Major cause of unprecedented

Arctic warming in January 2016 Critical role of an Atlantic

windstorm Sci Rep 7 40051 httpsdoiorg101038srep40051

Kriegsmann A and B Bruumlmmer 2014 Cyclone impact on sea ice

in the central Arctic Ocean Cryosphere 8 303ndash317 https

doiorg105194tc-8-303-2014

Krupnik I and Coauthors Eds 2011 Understanding Earthrsquos Polar

Challenges International Polar Year 2007ndash2008 International

Science Council 695 pp httpscouncilsciencepublications

understanding-earths-polar-challenges-international-polar-

year-2007-2008

Laursen V 1959 The second International Polar Year Annals of

the International Geophysical Year Vol 1 Pergamon 211ndash234

Lazzara M A G A Weidner L M Keller J E Thom and J C

Cassano 2012 Antarctic automatic weather station program

30 years of polar observations Bull Amer Meteor Soc 93

1519ndash1537 httpsdoiorg101175BAMS-D-11-000151


Lindsay R M Wensnahan A Schweiger and J Zhang 2014

Evaluation of seven different atmospheric reanalysis products

in the Arctic J Climate 27 2588ndash2606 httpsdoiorg

101175JCLI-D-13-000141

Liu Y J R Key S A Ackerman G G Mace and Q Zhang

2012 Arctic cloud macrophysical characteristics from Cloud-

Sat and CALIPSO Remote Sens Environ 124 159ndash173

httpsdoiorg101016jrse201205006

Loewe F 1936 TheGreenland ice cap as seen by a meteorologist

Quart J Roy Meteor Soc 62 359ndash377 httpsdoiorg

101002qj49706226601

mdashmdash 1967 On Antarctic pressure variations Quart J Roy Me-

teor Soc 93 373ndash380 httpsdoiorg101002qj49709339711

Madigan C T 1929 Tabulated and reduced records of the Cape

Denison station Adeacutelie Land Australasian Antarctic Expe-

dition 1911ndash1914 Science Rep Series B Vol 4 Government

Printer 28 pp

Mahoney A R J R Bockstoce D B Botkin H Eicken andRA

Nisbet 2011 Sea-ice distribution in the Bering and Chukchi

Seas Information from historical whaleshipsrsquo logbooks and

journalsArctic 64 465ndash477 httpsdoiorg1014430arctic4146

Manabe S and R Wetherald 1975 The effects of doubling the

CO2 concentration on the climate of a general circulation

model J Atmos Sci 32 3ndash15 httpsdoiorg101175

1520-0469(1975)0320003TEODTC20CO2

mdashmdash J Smagorinsky andR F Strickler 1965 Simulated climatology

of general circulation with a hydrologic cycle Mon Wea Rev

93 769ndash798 httpsdoiorg1011751520-0493(1965)0930769

SCOAGC23CO2

ManleyG 1944 Some recent contributions to the study of climate

change Quart J Roy Meteor Soc 73 197ndash219Morales Maqueda M A A J Wilmott and N R T Biggs 2004

Polynya dynamics A review of observations and modelingRev

Geophys 42 RG1004 httpsdoiorg1010292002RG000116

Marshunova M S and A A Mishin 1994 Handbook on the

Radiation Regime of the Arctic Basin (from the Drifting Sta-

tions) Hydrometeorological Publishing House 63 pp

Matthes F E 1946 The glacial anticyclone theory examined in

light of recent meteorological data from GreenlandmdashPart I

Trans Amer Geophys Union 27 324ndash341 httpsdoiorg

101029TR027i003p00324

mdashmdash and A D Belmont 1950 The glacial anticyclone theory exam-

ined in light of recent meteorological data fromGreenlandmdashPart

2 Trans Amer Geophys Union 31 174ndash182 httpsdoiorg

101029TR031i002p00174

Mawson D 1915 The Home of the Blizzard Vols 1 and 2

William Heinemann 687 pp

McFarquhar G M and Coauthors 2011 Indirect and Semi-

Direct Aerosol Campaign (ISDAC) The impact of Arctic

aerosols on clouds Bull Amer Meteor Soc 92 183ndash201

httpsdoiorg1011752010BAMS29351

Medley B and Coauthors 2013 Airborne-radar and ice-core

observations of annual snow accumulation over Thwaites

Glacier West Antarctica confirm the spatio-temporal vari-

ability of global and regional atmospheric models Geophys

Res Lett 40 3649ndash3654 httpsdoiorg101002grl50706

Meier W N and Coauthors 2014 Arctic sea ice in trans-

formation A review of recent observed changes and impacts

on biology and human activity Rev Geophys 52 185ndash217

httpsdoiorg1010022013RG000431

Monier E and Coauthors 2017 A review of and perspectives on

global change modeling for northern Eurasia Environ Res

Lett 12 083001 httpsdoiorg1010881748-9326aa7aae

Moreland W B 1958 Inside Antarctica No 3mdashThe Weather

Central at Little America Weatherwise 11 196ndash200 https

doiorg1010800043167219589925043

Namias J 1958 The general circulation of the lower troposphere

over Arctic regions and its relation to the general circulation

elsewhere Meteorology Part I Polar Atmosphere Sympo-

sium Pergamon Press 45ndash61

Nansen F 1898 Farthest North Being the Record of a Voyage of

Exploration of the Ship lsquolsquoFramrsquorsquo 1893-1896 and of a Fifteen

Monthsrsquo Sleigh Journey by Dr Nansen and Lieut Johansen

Vol 1 Harper amp Brothers 587 pp

Newman P A and Coauthors 2014 [Antarctica] Ozone depletion [in

Stateof theClimate in 2013]BullAmerMeteor Soc 95 (7) S152ndash

S156 httpsdoiorg1011752014BAMSStateoftheClimate1

Newton C W Ed 1972 Meteorology of the Southern Hemi-

sphereMeteor Monogr No 35 Amer Meteor Soc 267 pp

Nicolas J P and D H Bromwich 2011 Climate of West Ant-

arctica and influence of marine air intrusions J Climate 24


Nigro M A and J J Cassano 2014 Identification of surface wind

patterns over the Ross Ice Shelf Antarctica using self-

organizing maps Mon Wea Rev 142 2361ndash2378 https

doiorg101175MWR-D-13-003821

Noeumll BW K van deBerg E vanMeijgaard P KuipersMunneke

R S W van de Wal and M R van den Broeke 2015 Evalu-

ation of the updated regional climate model RACMO23

Summer snowfall impact on the Greenland Ice Sheet Cryo-

sphere 9 1831ndash1844 httpsdoiorg105194tc-9-1831-2015

Overland J E and M Wang 2016 Recent extreme Arctic tem-

peratures are due to a split polar vortex J Climate 29 5609ndash

5616 httpsdoiorg101175JCLI-D-16-03201

mdashmdash and mdashmdash 2018 Arctic-midlatitude weather linkages in

North America Polar Sci 16 1ndash9 httpsdoiorg101016

jpolar201802001

mdashmdash E Hanna I Hanssen-Bauer S-J Kim J E Walsh

M Wang US Bhatt and R L Thoman 2017 Surface air

temperature NOAA Arctic Report Card 2017 httpswww

arcticnoaagovReport-CardReport-Card-2017ArtMID

7798ArticleID700Surface-Air-Temperature

Page J 1900 Ice and ice movements in Bering Sea during the

spring months US Hydrographic Office Rep 18 pp

Palmeacuten E 1951 The role of atmospheric disturbances in the

general circulation Quart J Roy Meteor Soc 77 337ndash354


mdashmdash andCWNewton 1969Atmospheric Circulation Systems Their

Structure and Physical Interpretation Academic Press 603 pp

Palo T TVihma J Jaagus andE Jakobson 2017Observations of

temperature inversions over central Arctic sea ice in summer


101002qj3123

Parish T R and D H Bromwich 1987 The surface windfield over

the Antarctic Ice Sheets Nature 328 51ndash54 httpsdoiorg

101038328051a0

mdashmdash and R Walker 2006 A re-examination of the winds of

Adeacutelie Land Antarctica Aust Meteor Mag 55 105ndash117

Parkinson C L and J C Comiso 2013 On the 2012 record low

Arctic sea ice cover Geophys Res Lett 40 1356ndash1361

httpsdoiorg101002grl50349

Penner C M 1955 A three-front model for synoptic analyses

Quart J Roy Meteor Soc 81 89ndash91 httpsdoiorg101002

qj49708134710

Persson P O G 2012 Onset and end of the summer melt season

over sea ice Thermal structure and surface energy perspective


from SHEBA Climate Dyn 39 1349ndash1371 httpsdoiorg

101007s00382-011-1196-9

mdashmdash C W Fairall E L Andreas P S Guest and D K Perovich

2002 Measurements near the atmospheric surface group

tower at SHEBA Near-surface conditions and surface energy

budget J Geophys Res 107 8045 httpsdoiorg101029

2000JC000705

Pettersen S 1950 Some aspects of the general circulation of the

atmosphere Centenary Proceedings of the Royal Meteoro-

logical Society Royal Meteorological Society 120ndash153

Phillips N A 1956 The general circulation of the atmosphere A

numerical experiment Quart J Roy Meteor Soc 82 123ndash

164 httpsdoiorg101002qj49708235202

Pithan F and T Mauritsen 2014 Arctic amplification dominated

by temperature feedbacks in contemporary climate models


mdashmdash B Medeiros and T Mauritsen 2014 Mixed-phase clouds

cause climate model biases in Arctic wintertime temperature

inversions Climate Dyn 43 289ndash303 httpsdoiorg101007

s00382-013-1964-9

Poli P and Coauthors 2016 ERA-20C An Atmospheric Re-

analysis of the Twentieth Century J Climate 29 4083ndash4097


Polyakov I V and Coauthors 2003 Long-term ice variability in

Arctic marginal seas J Climate 16 2078ndash2085 httpsdoiorg

1011751520-0442(2003)0162078LIVIAM20CO2

Powers J K W Manning D H Bromwich J J Cassano and

A M Cayette 2012 A decade of Antarctic science support

through AMPS Bull Amer Meteor Soc 93 1699ndash1712


Rae R W 1951 The Climate of the Canadian Archipelago Tor-

onto Department of Transport 90 pp

Reed R J and B A Kunkel 1960 The arctic circulation in

summer J Meteor 17 489ndash506 httpsdoiorg101175

1520-0469(1960)0170489TACIS20CO2

Riffenburgh B 2006 Encyclopedia of the Antarctic Taylor and

Francis 1272 pp

Ringgold C and J Rodgers 1950 United States North Pacific

Exploring Expedition under Commanders Ringgold and

Rodgers 1853-1856 Biodiversity Heritage Library 8 pp

httpsdoiorg105962bhltitle147272

Rinke A M Maturilli R M Graham H Matthes D Handorf

L Cohen S R Hudson and J C Moore 2017 Extreme

cyclone events in the Arctic Wintertime variability and

trends Environ Res Lett 12 094006 httpsdoiorg101088

1748-9326aa7def

Rodionov S N J E Overland and N A Bond 2005 The

Aleutian low and winter climatic conditions in the Bering Sea

Part I Classification J Climate 18 160ndash177 httpsdoiorg

101175JCLI32531

Rusin N P 1964 Meteorological and Radiational Regime of

Antarctica Israel Program for Scientific Translations 355 pp

Scherhag R 1936 Eine bemerkenswerte Klimaanderung uber

Nordeuropa Ann Hydrogr Marit Meteor 64 96ndash100

mdashmdash 1960 Stratospheric temperature changes and the associated

changes in pressure distribution J Meteor 17 575ndash582 https

doiorg1011751520-0469(1960)0170575STCATA20CO2

SchleyW S 1887 TheGreely Relief Expedition 1884 US NavyRep

GovernmentPrintingOffice 75pphttpsbooksgooglecombooks

id5TZblAAAAMAAJampprintsec5frontcoverampsource5gbs_ge_

summary_rampcad50v5onepageampqampf5false

Schlosser E B Stenni M Valt A Cagnati J G Powers K W

Manning M Raphael and M G Duda 2016 Precipitation and

synoptic regime in two extreme years 2009 and 2010 at Dome C

AntarcticamdashImplications for ice core interpretationAtmos Chem

Phys 16 4757ndash4770 httpsdoiorg105194acp-16-4757-2016Schmid B R E Ellingson and G M McFarquhar 2016 ARM

aircraft measurements The Atmospheric Radiation Mea-

surement (ARM) Program The First 20 Years Meteor

Monogr No 57 Amer Meteor Soc httpsdoiorg101175

AMSMONOGRAPHS-D-15-00421

Schweiger A J and J R Key 1994 Arctic Ocean radiative fluxes

and cloud forcing from the ISCCP C2 cloud dataset 1983ndash

1990 J Appl Meteor 33 948ndash963 httpsdoiorg101175

1520-0450(1994)0330948AORFAC20CO2

mdashmdash R Lindsay J Zhang M Steele and H Stern 2011 Un-

certainty in modeled Arctic sea ice volume J Geophys Res

116 C00D06 httpsdoiorg1010292011JC007084

Schwerdtfeger W 1970 The climate of the Antarctic Climates of

the Polar Regions S Orvig EdWorld Survey of Climatology

Vol 14 Elsevier 253ndash355

mdashmdash 1972 The vertical variation of the wind through the friction-

layer of theGreenland ice capTellus 24 13ndash16 httpsdoiorg

103402tellusav24i110615

Screen J A and I Simmonds 2010 The central role of diminishing

sea ice in recent Arctic temperature amplification Nature 464

1334ndash1337 httpsdoiorg101038Znature09051

mdashmdash and Coauthors 2018 Consistency and discrepancy in the atmo-

spheric response to Arctic sea-ice loss across climate modelsNat

Geosci 11 155ndash163 httpsdoiorg101038s41561-018-0059-y

SerrezeM C AH Lynch andM P Clark 2001 TheArctic frontal

zone as seen in the NCEPndashNCAR Reanalysis J Climate


TAFZAS20CO2

mdashmdashA P Barrett J C Stroeve DM Kindig andMMHolland

2009 The emergence of surface-based Arctic amplification

Cryosphere 3 11ndash19 httpsdoiorg105194tc-3-11-2009

Shapiro M A T Hampel and A J Krueger 1987 The Arctic

tropopause foldMonWea Rev 115 444ndash454 httpsdoiorg

1011751520-0493(1987)1150444TATF20CO2

Shiklomanov A I and R B Lammers 2014 River ice re-

sponses to a warming ArcticmdashRecent evidence from Rus-

sian rivers Environ Res Lett 9 035008 httpsdoiorg

1010881748-932693035008

Shuman J K NM Tchebakova E I Parfenova A J Soja H H

Shugart D Ershov and K Holcomb 2015 Forest forecasting

with vegetation models across Russia Can J For Res 45

175ndash184 httpsdoiorg101139cjfr-2014-0138

Shupe M D and J M Intrieri 2004 Cloud radiative forcing of the

Arctic surface The influence of cloud properties surface albedo

and solar zenith angle J Climate 17 616ndash628 httpsdoiorg

1011751520-0442(2004)0170616CRFOTA20CO2

mdashmdash V P Walden E Eloranta T Uttal J R Campbell S M

Starkweather and M Shiobara 2011 Clouds at Arctic at-

mospheric observatories Part I Occurrence and macro-

physical properties J Appl Meteor Climatol 50 626ndash644

httpsdoiorg1011752010JAMC24671

mdashmdash M Tjernstrom and P O G Persson 2015 [The Arctic]

Challenge of Arctic clouds and their implications for surface

radiation [in lsquolsquoState of the Climate in 2014rsquorsquo] Bull Amer

Meteor Soc 96 (7) S130ndashS131 httpsjournalsametsocorg

doisuppl1011752015BAMSStateoftheClimate1suppl_

file101175_2015BAMSStateoftheClimate3pdf

mdashmdash and Coauthors 2016 MOSAiC science plan International

Arctic Science Committee Rep 85 pp httpswwwmosaic-


expeditionorgfileadminuser_uploadMOSAiCDocuments

MOSAiC_SciencePlan-V20pdf

Simmonds I and K Keay 2009 Extraordinary Arctic sea ice

reductions and their relationships with storm behavior over

1979ndash2008 Geophys Res Lett 36 L19715 httpsdoiorg

1010292009GL039810

mdashmdash and I Rudeva 2012 The great Arctic cyclone of August

2012 Geophys Res Lett 39 L23709 httpsdoiorg101029

2012GL054259

Simpson E 1890 Report of ice and ice movements in Bering Sea

and Arctic Basin US Hydrographic Office Rep 92 25 pp

httpsbabelhathitrustorgcgiptid5hvd32044089355788view51upseq53

Simpson G C 1919 Weather Maps and Pressure Curves Vol II

British Antarctic Expedition 1910ndash1913 Meteorology Thacker

Spink amp Company 138 pp

mdashmdash 1921 Discussion Vol I British Antarctic Expedition 1910ndash

1913 Meteorology Thacker Spink amp Company 355 pp

mdashmdash 1923 Tables Vol III British Antarctic Expedition 1910ndash

1913 Meteorology Thacker Spink and Company 848 pp

Skamarock W C 2004 Evaluating mesoscale NWP models us-

ing kinetic energy spectra Mon Wea Rev 132 3019ndash3032

httpsdoiorg101175MWR28301

Smagorinsky J 1983 The beginnings of numerical weather pre-

diction and general circulation modeling Early recollections

Advances in Geophysics Vol 25 Academic Press 3ndash37

httpsdoiorg101016S0065-2687(08)60170-3

Smirnova J and P Golubkin 2017 Comparing polar lows in at-

mospheric reanalyses Arctic System Reanalysis versus ERA-

Interim Mon Wea Rev 145 2375ndash2383 httpsdoiorg

101175MWR-D-16-03331

Solomon S 2001 The Coldest March Scottrsquos Fatal Antarctic Ex-

pedition Yale University Press 383 pp

mdashmdash R R Garcia F S Rowland and D J Wuebbles 1986 On

the depletion of Antarctic ozoneNature 321 755ndash758 https

doiorg101038321755a0

Stolarski R S A J Krueger M R Shoeberl R D McPeters

P A Newman and J C Alpert 1986 Nimbus 7 satellite

measurements of the springtime Antarctic ozone decrease

Nature 322 808ndash811 httpsdoiorg101038322808a0

Strahan S E and A R Douglass 2018 Decline in Antarctic

ozone depletion and lower stratospheric chlorine determined

from Aura Microwave Limb Sounder observations Geophys

Res Lett 45 382ndash390 httpsdoiorg1010022017GL074830

Stramler K A D Del Genio and W B Rossow 2011 Synopti-

cally driven Arctic winter states J Climate 24 1747ndash1762

httpsdoiorg1011752010JCLI38171

Streletskiy D A A B Sherstiukov O W Fraunfeld and F E

Nelson 2015 Changes in the 1963ndash2013 shallow ground ther-

mal regime in Russian permafrost regions Environ Res Lett

10 125005 httpsdoiorg1010881748-93261012125005

Stroeve J L C Hamilton C M Bitz and E Blanchard-

Wrigglesworth 2014 Predicting September sea ice Ensemble

skill of the SEARCH sea ice outlook 2008ndash2013Geophys Res

Lett 41 2411ndash2418 httpsdoiorg1010022014GL059388

mdashmdash E Blanchard-Wrigglesworth V Guemas S Howell

F Massonnet and S Tietsche 2015 Improving predictions of

Arctic sea ice extent Eos Trans Amer Geophys Union 96

httpsdoiorg1010292015EO031431

Taylor P C M Cai A Hu J Meehl W Washington and G J

Zhang 2013 A decomposition of feedback contributions to

polar warming amplification J Climate 26 7023ndash7043 https

doiorg101175JCLI-D-12-006961

Teisserenc de Bort L P 1883 Etude sur lrsquohiver de 1879-80 et

recherches sur lrsquoinfluence de la position des grands centres

drsquoaction de lrsquoatmosphegravere dans les hivers anormaux (Study on

the winter of 1879ndash80 and research on the influence of the

position of the great atmospheric centers of action in abnormal

winters) Ann Soc Meacuteteacuteor France 31 70ndash79Thomas M K 1971 A brief history of the Canadian meteoro-

logical services part 2 1930ndash1939Atmosphere 9 1ndash7 https

doiorg1010800004697319719648324

ThompsonDW J and S Solomon 2002 Interpretation of recent

Southern Hemisphere climate change Science 296 895ndash899

httpsdoiorg101126science1069270

mdashmdashmdashmdash P J Kushner M H England K MMcGrise andD J

Karoly 2011 Signatures of the Antarctic ozone hole in

Southern Hemisphere surface climate change Nat Geosci 4

741ndash749 httpsdoiorg101038ngeo1296

Thomson A 1948 The growth of meteorological knowledge of

the Canadian ArcticArctic 1 34ndash43 httpsdoiorg1014430

arctic3995

ThorndikeA S andRColony 1981ArcticOceanBuoy Program

DataReport 1 January 1980ndash31December 1980 University of

Washington Rep 131 pp httpiabpaplwashingtonedupdfs

AOBP1980Thorndikepdf

Timmermans M L J Toole and R Krishfield 2018Warming of the

interior Arctic Ocean linked to sea ice losses at the basin margins

Sci Adv 4 eaat6773 httpsdoiorg101126sciadvaat6773

Titchner H A and N A Rayner 2014 The Met Office Hadley

Centre sea ice and sea surface temperature data set version 2

1 Sea ice concentrations J Geophys Res Atmos 119 2864ndash

2889 httpsdoiorg1010022013JD020316

Tjernstrom M J Sedlar and M D Shupe 2008 How well do

regional climate models reproduce radiation and clouds in

the Arctic An evaluation of ARCMIP simulations J Appl

Meteor Climatol 47 2405ndash2422 httpsdoiorg101175

2008JAMC18451

mdashmdash and Coauthors 2014 The Arctic Summer Cloud Ocean

Study (ASCOS) Overview and experimental design At-

mos Chem Phys 14 2823ndash2869 httpsdoiorg105194

acp-14-2823-2014

Tomas R A C Deser and L Sun 2016 The role of ocean heat

transport in the global climate response to projected Arctic

sea ice loss J Climate 29 6841ndash6858 httpsdoiorg101175

JCLI-D-15-06511

Tyson G E and H W Howgate 1879 The Cruise of the Florence

or Extracts from the Journal of the PreliminaryArctic Expedition

of 1877ndashrsquo78 J J Chapman 188 pp httpsbabelhathitrustorg

cgiptid5aeuark13960t46q2g92jview51upseq57

Untersteiner N A S Thorndike D A Rothrock and K L

Hunkins 2009 AIDJEX revisited A look back at the US-

Canadian Arctic Ice Dynamics Joint Experiment 1970ndash78

Arctic 60 327ndash336 httpsdoiorg1014430arctic233

US Coast Survey 1869 Report of the superintendent of the

United States Coast Survey showing the progress of the

Survey during the year 1867 US Coast Survey Rep

334 pp

US Hydrographic Office 1946 Ice Atlas of the Northern Hemi-

sphere Vol 550 US Hydrographic Office 106 pp

US National Archives 1964 Records relating to theUnited States

surveying expedition to the North Pacific Ocean 1852ndash1863

National Archives and Records Service General Services

Administration Microfilm


Uttal T and Coauthors 2002 Surface heat budget of the Arctic

Ocean Bull Amer Meteor Soc 83 255ndash275 httpsdoiorg

1011751520-0477(2002)0830255SHBOTA23CO2

van de Berg W J M R van den Broeke C H Reijmer and

E van Meijgaard 2005 Characteristics of Antarctic surface

mass balance 1958ndash2002 using a regional atmospheric climate

model Ann Glaciol 41 97ndash104 httpsdoiorg103189

172756405781813302

van Loon H 1967 The half-yearly oscillations in middle and high

southern latitudes and the coreless winter J Atmos Sci


THYOIM20CO2

Vavrus S J F Wang J E Martin J A Francis Y Peings and

J Cattiaux 2017 Changes in North American atmospheric

circulation and extreme weather Influence of Arctic amplifi-

cation and Northern Hemisphere snow cover J Climate 30

4317ndash4333 httpsdoiorg101175JCLI-D-16-07621

Verlinde J and Coauthors 2007 The Mixed-Phase Arctic Cloud

Bull Amer Meteor Soc 88 205ndash221 httpsdoiorg101175BAMS-88-2-205

Vernon C L J L Bamber J E Box M R van den Broeke

X Fettweis E Hanna and P Huybrechts 2013 Surface mass

balance model intercomparison for the Greenland ice sheet


Viterbo P and A K Betts 1999 The impact on ECMWF fore-

casts of changes in the albedo of the boreal forests in the

presence of snow J Geophys Res 104 27 803ndash27 810 https

doiorg1010291998JD200076

von Helmholtz H 1888 Uumlber atmosphaumlrische Bewegungen (On

atmospheric movements) Meteor Z 5 329ndash340Voumlroumlsmarty C and Coauthors 2002 Arctic-CHAMP A program

to study arctic hydrology and its role in global change Eos


1010292002EO000167

Vowinckel E and S Orvig 1971 The Climate of the North Polar

Basin Climates of the Polar Regions S Orvig Ed World

Survey of Climatology Vol 14 Elsevier 129ndash252

Walker G T 1923 Correlation in seasonal variation of weather

VIII A preliminary study of world weather Mem Indian

Meteor Dep 24 75ndash131

Walsh J E and W L Chapman 1998 Arctic cloudndashradiationndash

temperature associations in observational data and atmo-

spheric reanalyses J Climate 11 3030ndash3045 httpsdoiorg

1011751520-0442(1998)0113030ACRTAI20CO2

mdashmdash and mdashmdash 2001 20th-century sea-ice variations from obser-

vational data Ann Glaciol 33 444ndash448 httpsdoiorg

103189172756401781818671

mdashmdash F Fetterer J S Stewart andW L Chapman 2016 A database

for depicting Arctic sea ice variations back to 1850Geogr Rev

107 89ndash107 httpsdoiorg101111j1931-0846201612195x

Wang G and W Cai 2013 Climate-change impact on the 20th-

century relationship between the southern annular mode and

global mean temperature Sci Rep 3 2039 httpsdoiorg

101038srep02039

Weather Bureau 1925 Climatological data herein from the es-

tablishment of the stations to 1921 inclusive USDepartment

of Agriculture Rep 277 pp

Weingartner T J S Danielson Y Sasaki V Pavlov and

M Kulakov 1999 The Siberian Coastal Current A wind- and

buoyancy-forcedArctic coastal current JGeophys ResOceans

104 29 697ndash29 713 httpsdoiorg1010291999JC900161

Weyprecht C 1875 Die 2 Oumlsterr-Ungarische Nordpolar-

Expedition unter Weyprecht und Payer 18724 Schiffrsquoslieut

Weyprechtrsquos Vortrag uumlber die von ihm geleiteten wissen-

schaftlichen Beobachtungen gehalten in Wien 18 Januar

1875 (The second Austro-Hungarian Arctic Expedition under

Weyprecht and Payer 187274 Shiprsquos LieutenantWeyprechtrsquos

lecture on his scientific observations held in Vienna 18 Janu-

ary 1875) Mittheilungen aus Justus Perthesrsquo Geographischer

Anstalt Vol 21 65ndash72

Wiese W 1924 Polareis und Atmospharische Schwankungen

(Polar ice and atmospheric fluctuations) Geogr Ann 6

273ndash299

Wilkes C 1845a Narrative of the United States Exploring Ex-

pedition during the Years 1838 1839 1840 1841 1842 Vol

1 Lea and Blanchard 434 pp httpsarchiveorgdetails

narrativeofunite01wilkuoftpagen0

mdashmdash 1845b Narrative of the United States Exploring Expedi-

tion during the Years 1838 1839 1840 1841 1842 Vol 4

Lea and Blanchard 539 pp httpsarchiveorgdetails


Wilson C V 1958 Synoptic regimes of the lower Arctic tropo-

sphere during 1955 McGill University Arctic Meteorology

Research Group Publ 8 57 pp

Wood K R and J E Overland 2006 Climate lessons from the

first International Polar Year Bull Amer Meteor Soc 871685ndash1697 httpsdoiorg101175BAMS-87-12-1685

mdashmdash and mdashmdash 2010 Early 20th century Arctic warming in retro-

spect Int J Climatol 30 1269ndash1279 httpsdoiorg101002joc1973

Woodgate R A K Aagaard and T J Weingartner 2005

Monthly temperature salinity and transport variability of the

Bering Strait through flow Geophys Res Lett 32 L04601httpsdoiorg1010292004GL021880

Yamanouchi T 2011 Early 20th century warming in the Arctic A re-

viewPolar Sci 5 53ndash71 httpsdoiorg101016jpolar201010002

Zhang J R Lindsey A Schweiger and M Steele 2013 The

impact of an intense summer cyclone on 2012 Arctic sea

ice extent Geophys Res Lett 40 720ndash726 httpsdoiorg

101002grl50190

Zygmuntowska M T Mauritsen J Quaas and L Kaleschke 2012

Arctic clouds and surface radiationmdashA critical comparison of

satellite retrievals and theERA-Interim reanalysisAtmos Chem

Phys 12 6667ndash6677 httpsdoiorg105194acp-12-6667-2012


summarize the evolution of polar meteorology in both

hemispheres beginning with measurements made dur-

ing early expeditions and concluding with the recent

decades in which polar meteorology has been central

to global challenges such as the Antarctic ozone hole

weather prediction and climate change

2 Review of the pre-1919 period (before theestablishment of the American MeteorologicalSociety)

The development of polar meteorology in the nine-

teenth century is inextricably linked to the engines of

commerce territorial expansion and geographic explo-

ration From an American perspective these begin with

theUS South Seas Exploring Expedition (also known as

theWilkes Expedition or simply theUS Ex Ex) during

1838ndash42 (Wilkes 1845ab) followed by the lesser-known

US North Pacific Exploring and Surveying Expedition

(RinggoldndashRodgers Expedition) of 1853ndash56 (Ringgold

and Rodgers 1950 US National Archives 1964) both

US Navy expeditions TheUS Navy often with private

support contributed to the search for the missing British

expedition of Sir JohnFranklin in theArctic islands north

of Canada and to a number of other early explorations

along the west coast of Greenland These efforts added

to early knowledge of Arctic meteorology mainly by

providing observations (eg Kane 1854 Kane and Schot

1859 Tyson and Howgate 1879 Bessels 1876) for com-

parison with modern observational data and also de-

scriptions of the atmospheric (as well as ice and ocean)

phenomena they encountered Steep inversions and as-

sociated mirages ice fog sea ice ridges and leads and

floating ice islands are examples The first documented

measurements of surface-based inversions were actually

made by measuring temperatures from the lsquolsquocrowrsquos nestrsquorsquo

at 32 m above sea level on Nansenrsquos Fram expedition

(Palo et al 2017) The Army Signal Service the Coast

Survey and the Smithsonian Institution frequently sup-

ported observers supplied meteorological instruments

and provided expert data reduction and publishing as-

sistance to these endeavors (eg Abbe 1893)

The Wilkes Expedition reached Antarctica but there

were no follow-up scientific expeditions to this region

organized in the United States until the first of the Byrd

expeditions in 1928 (Riffenburgh 2006) In the Arctic

however the development of the whaling industry in the

Chukchi and Beaufort Seas beginning in 1848 the pur-

chase of Alaska from Russia in 1867 and the rise of

collaborative scientific exploration of the polar regions

as demonstrated by the landmark first International

Polar Year (IPY 1881ndash84) provided steady impetus for

exploration and research in the far north

The ill-fated 1879 expedition of the USS Jeannette

which set out to reach the North Pole by following a hy-

pothetical lsquolsquothermometric gatewayrsquorsquo through Bering Strait

to an open polar sea (Bent 1872 Hayes 1867) was perhaps

the last to be motivated in large part by speculative geo-

graphical notions about the Arctic including the possi-

bility of an ice-free polar ocean Today the Jeannette

expedition or more directly the part of its wreck that

turned up years later in Greenland is known as an in-

spiration for Fridtjof Nansenrsquos attempt to drift with the

sea ice across the North Pole in the Fram (Nansen 1898)

While expeditions like those carriedoutwith the Jeannette

and the Fram certainly pressed the frontier of discoverymdash

often at a high costmdashand produced extremely valuable

results the underlying story of scientific progress is per-

haps best revealed in the sustained even routine work to

measure describe and map the lands and oceans their

resources and the weather and climate Innovation was a

key factor from the beginning as new tools for observing

the deep sea and the upper atmosphere were constantly

being developed along with more capable ships (and

later aircraft) for operation in harsh polar conditions The

value to science of the vast archive of data that was dili-

gently collected by hundreds of people over these years is

still being realized

a Early investigations of weather and ice

The earliest sustained and systematic investigations of

the weather climate and oceanography of the Arctic by

the United States came with the Alaska Purchase (https

wwwlocgovrrprogrambibourdocsAlaskahtml) The

US Coast Survey and the Revenue Cutter Service (pre-

decessor of the US Coast Guard) began with an initial

reconnaissance in 1867 with a view toward collecting in-

formation necessary for the production of navigational

charts and for theCoast Pilot ofAlaska (USCoast Survey

1869) Starting in 1880 the Revenue Cutter ServiceCoast

Guard made annual summer cruises to the northern Be-

ring and Chukchi Seas and in the process collected a

nearly unbroken series of marine-meteorological and sea

ice observations that extends to the present day (Fig 21-1)

The US Navyrsquos Bureau of Navigation also issued

Findlayrsquos (1869)Directory for the Behringrsquos Sea and Coast

of Alaska a compendium of previously published infor-

mation about the region including a review of weather

and sea ice conditions in the Arctic recorded by earlier

explorers over the previous 100 years back to Cook and

Clerkersquos voyages in 1778 and 1779 (Beaglehole 1967)

At the same time the US Army garrisoned Sitka

(New Archangelsk) and a few other former Russian

outposts forming the beginning of the station network in

Alaska that would later be developed by the Army Signal

Service (as the first official weather agency then known as















































































































































































































































































1958 to 2010 (Bromwich et al 2013 2014)





























































































Northwest)































































































full_report2017pdf]



















































































continent















































































Force base











f Evolving thought























(Jones 1987)



























































































































Phillips 1956)





















































































































































































































































































Weather Watch





































e Arctic clouds




















































































































































































































































































ranges






























SYSTEM

















































































































both polar regions
















NCAR)








































































manuscript

APPENDIX










































observation period




































































































































































f SEARCH (2010s)









































REFERENCES





Rep (Part II) 53 pp









2011BAMS32181













doiorg101002wcc337




















Studley Co 40 pp









1010022017GL075841



























doiorg1011751520-0442(2004)0173415PMSOTW20CO2











j1600-0870201100537x








ngeo2016



BAMS-D-16-02151


29ndash31





1010881748-9326102025003



92 (4) 429ndash522





264 httpsdoiorg101080070559002013798582











JCLI-D-15-07751









doiorg101175MWR-D-11-001821





2012GL053385






doiorg101002qj776



JCLI-D-14-004471







JCLI-D-17-02961











1520-0442(1996)0091731OOACAR20CO2




nyp33433000204663

















doiorg1010292018GL077092











1011751520-0469(1945)0020135SMAOTG20CO2



101063PT32449




doiorg101175MWR-D-12-000911



















315207a0



































101002qj2401



101175JAS-33531



2001JD001526



(1960)0170036TDCOTA20CO2



doiorg101002qj49708636802














[154MWIA]20CO2










TGGA20CO2




doiorg101007s00382-012-1512-z



86961989tb07053x











doiorg1011751520-0493(1922)50589aTCA20CO2






BF01054476




BAMS-D-14-002461




1011751520-0477(1992)0731824ISMSAF20CO2










ASAIW20CO2




91015003






doiorg105194tc-8-303-2014





year-2007-2008











101175JCLI-D-13-000141







101002qj49706226601






Printer 28 pp








1520-0469(1975)0320003TEODTC20CO2




SCOAGC23CO2











101029TR027i003p00324




101029TR031i002p00174





















doiorg1010800043167219589925043




















doiorg101175MWR-D-13-003821











jpolar201802001
















101002qj3123



101038328051a0








qj49708134710





101007s00382-011-1196-9





2000JC000705






164 httpsdoiorg101002qj49708235202







s00382-013-1964-9






1011751520-0442(2003)0162078LIVIAM20CO2









1520-0469(1960)0170489TACIS20CO2


Francis 1272 pp









1748-9326aa7def




101175JCLI32531







doiorg1011751520-0469(1960)0170575STCATA20CO2

















1520-0450(1994)0330948AORFAC20CO2









103402tellusav24i110615










TAFZAS20CO2






1011751520-0493(1987)1150444TATF20CO2




1010881748-932693035008








1011751520-0442(2004)0170616CRFOTA20CO2




















1010292009GL039810



2012GL054259

















httpsdoiorg101016S0065-2687(08)60170-3




101175MWR-D-16-03331





doiorg101038321755a0















10 125005 httpsdoiorg1010881748-93261012125005












doiorg101175JCLI-D-12-006961








doiorg1010800004697319719648324










arctic3995











2889 httpsdoiorg1010022013JD020316





2008JAMC18451




acp-14-2823-2014




JCLI-D-15-06511












334 pp










1011751520-0477(2002)0830255SHBOTA23CO2





172756405781813302




THYOIM20CO2















doiorg1010291998JD200076





1010292002EO000167










1011751520-0442(1998)0113030ACRTAI20CO2



103189172756401781818671







101038srep02039



















273ndash299
























101002grl50190



















































































































































































































































































1958 to 2010 (Bromwich et al 2013 2014)





























































































Northwest)































































































full_report2017pdf]



















































































continent















































































Force base











f Evolving thought























(Jones 1987)



























































































































Phillips 1956)





















































































































































































































































































Weather Watch





































e Arctic clouds




















































































































































































































































































ranges






























SYSTEM

















































































































both polar regions
















NCAR)








































































manuscript

APPENDIX










































observation period




































































































































































f SEARCH (2010s)









































REFERENCES





Rep (Part II) 53 pp









2011BAMS32181













doiorg101002wcc337




















Studley Co 40 pp









1010022017GL075841



























doiorg1011751520-0442(2004)0173415PMSOTW20CO2











j1600-0870201100537x








ngeo2016



BAMS-D-16-02151


29ndash31





1010881748-9326102025003



92 (4) 429ndash522





264 httpsdoiorg101080070559002013798582











JCLI-D-15-07751









doiorg101175MWR-D-11-001821





2012GL053385






doiorg101002qj776



JCLI-D-14-004471







JCLI-D-17-02961











1520-0442(1996)0091731OOACAR20CO2




nyp33433000204663

















doiorg1010292018GL077092











1011751520-0469(1945)0020135SMAOTG20CO2



101063PT32449




doiorg101175MWR-D-12-000911



















315207a0



































101002qj2401



101175JAS-33531



2001JD001526



(1960)0170036TDCOTA20CO2



doiorg101002qj49708636802














[154MWIA]20CO2










TGGA20CO2




doiorg101007s00382-012-1512-z



86961989tb07053x











doiorg1011751520-0493(1922)50589aTCA20CO2






BF01054476




BAMS-D-14-002461




1011751520-0477(1992)0731824ISMSAF20CO2










ASAIW20CO2




91015003






doiorg105194tc-8-303-2014





year-2007-2008











101175JCLI-D-13-000141







101002qj49706226601






Printer 28 pp








1520-0469(1975)0320003TEODTC20CO2




SCOAGC23CO2











101029TR027i003p00324




101029TR031i002p00174





















doiorg1010800043167219589925043




















doiorg101175MWR-D-13-003821











jpolar201802001
















101002qj3123



101038328051a0








qj49708134710





101007s00382-011-1196-9





2000JC000705






164 httpsdoiorg101002qj49708235202







s00382-013-1964-9






1011751520-0442(2003)0162078LIVIAM20CO2









1520-0469(1960)0170489TACIS20CO2


Francis 1272 pp









1748-9326aa7def




101175JCLI32531







doiorg1011751520-0469(1960)0170575STCATA20CO2

















1520-0450(1994)0330948AORFAC20CO2









103402tellusav24i110615










TAFZAS20CO2






1011751520-0493(1987)1150444TATF20CO2




1010881748-932693035008








1011751520-0442(2004)0170616CRFOTA20CO2




















1010292009GL039810



2012GL054259

















httpsdoiorg101016S0065-2687(08)60170-3




101175MWR-D-16-03331





doiorg101038321755a0















10 125005 httpsdoiorg1010881748-93261012125005












doiorg101175JCLI-D-12-006961








doiorg1010800004697319719648324










arctic3995











2889 httpsdoiorg1010022013JD020316





2008JAMC18451




acp-14-2823-2014




JCLI-D-15-06511












334 pp










1011751520-0477(2002)0830255SHBOTA23CO2





172756405781813302




THYOIM20CO2















doiorg1010291998JD200076





1010292002EO000167










1011751520-0442(1998)0113030ACRTAI20CO2



103189172756401781818671







101038srep02039



















273ndash299
























101002grl50190





































































































































































































































1958 to 2010 (Bromwich et al 2013 2014)





























































































Northwest)































































































full_report2017pdf]



















































































continent















































































Force base











f Evolving thought























(Jones 1987)



























































































































Phillips 1956)





















































































































































































































































































Weather Watch





































e Arctic clouds




















































































































































































































































































ranges






























SYSTEM

















































































































both polar regions
















NCAR)








































































manuscript

APPENDIX










































observation period




































































































































































f SEARCH (2010s)









































REFERENCES





Rep (Part II) 53 pp









2011BAMS32181













doiorg101002wcc337




















Studley Co 40 pp









1010022017GL075841



























doiorg1011751520-0442(2004)0173415PMSOTW20CO2











j1600-0870201100537x








ngeo2016



BAMS-D-16-02151


29ndash31





1010881748-9326102025003



92 (4) 429ndash522





264 httpsdoiorg101080070559002013798582











JCLI-D-15-07751









doiorg101175MWR-D-11-001821





2012GL053385






doiorg101002qj776



JCLI-D-14-004471







JCLI-D-17-02961











1520-0442(1996)0091731OOACAR20CO2




nyp33433000204663

















doiorg1010292018GL077092











1011751520-0469(1945)0020135SMAOTG20CO2



101063PT32449




doiorg101175MWR-D-12-000911



















315207a0



































101002qj2401



101175JAS-33531



2001JD001526



(1960)0170036TDCOTA20CO2



doiorg101002qj49708636802














[154MWIA]20CO2










TGGA20CO2




doiorg101007s00382-012-1512-z



86961989tb07053x











doiorg1011751520-0493(1922)50589aTCA20CO2






BF01054476




BAMS-D-14-002461




1011751520-0477(1992)0731824ISMSAF20CO2










ASAIW20CO2




91015003






doiorg105194tc-8-303-2014





year-2007-2008











101175JCLI-D-13-000141







101002qj49706226601






Printer 28 pp








1520-0469(1975)0320003TEODTC20CO2




SCOAGC23CO2











101029TR027i003p00324




101029TR031i002p00174





















doiorg1010800043167219589925043




















doiorg101175MWR-D-13-003821











jpolar201802001
















101002qj3123



101038328051a0








qj49708134710





101007s00382-011-1196-9





2000JC000705






164 httpsdoiorg101002qj49708235202







s00382-013-1964-9






1011751520-0442(2003)0162078LIVIAM20CO2









1520-0469(1960)0170489TACIS20CO2


Francis 1272 pp









1748-9326aa7def




101175JCLI32531







doiorg1011751520-0469(1960)0170575STCATA20CO2

















1520-0450(1994)0330948AORFAC20CO2









103402tellusav24i110615










TAFZAS20CO2






1011751520-0493(1987)1150444TATF20CO2




1010881748-932693035008








1011751520-0442(2004)0170616CRFOTA20CO2




















1010292009GL039810



2012GL054259

















httpsdoiorg101016S0065-2687(08)60170-3




101175MWR-D-16-03331





doiorg101038321755a0















10 125005 httpsdoiorg1010881748-93261012125005












doiorg101175JCLI-D-12-006961








doiorg1010800004697319719648324










arctic3995











2889 httpsdoiorg1010022013JD020316





2008JAMC18451




acp-14-2823-2014




JCLI-D-15-06511












334 pp










1011751520-0477(2002)0830255SHBOTA23CO2





172756405781813302




THYOIM20CO2















doiorg1010291998JD200076





1010292002EO000167










1011751520-0442(1998)0113030ACRTAI20CO2



103189172756401781818671







101038srep02039



















273ndash299
























101002grl50190

































































































































































































































1958 to 2010 (Bromwich et al 2013 2014)





























































































Northwest)































































































full_report2017pdf]



















































































continent















































































Force base











f Evolving thought























(Jones 1987)



























































































































Phillips 1956)





















































































































































































































































































Weather Watch





































e Arctic clouds




















































































































































































































































































ranges






























SYSTEM

















































































































both polar regions
















NCAR)








































































manuscript

APPENDIX










































observation period




































































































































































f SEARCH (2010s)









































REFERENCES





Rep (Part II) 53 pp









2011BAMS32181













doiorg101002wcc337




















Studley Co 40 pp









1010022017GL075841



























doiorg1011751520-0442(2004)0173415PMSOTW20CO2











j1600-0870201100537x








ngeo2016



BAMS-D-16-02151


29ndash31





1010881748-9326102025003



92 (4) 429ndash522





264 httpsdoiorg101080070559002013798582











JCLI-D-15-07751









doiorg101175MWR-D-11-001821





2012GL053385






doiorg101002qj776



JCLI-D-14-004471







JCLI-D-17-02961











1520-0442(1996)0091731OOACAR20CO2




nyp33433000204663

















doiorg1010292018GL077092











1011751520-0469(1945)0020135SMAOTG20CO2



101063PT32449




doiorg101175MWR-D-12-000911



















315207a0



































101002qj2401



101175JAS-33531



2001JD001526



(1960)0170036TDCOTA20CO2



doiorg101002qj49708636802














[154MWIA]20CO2










TGGA20CO2




doiorg101007s00382-012-1512-z



86961989tb07053x











doiorg1011751520-0493(1922)50589aTCA20CO2






BF01054476




BAMS-D-14-002461




1011751520-0477(1992)0731824ISMSAF20CO2










ASAIW20CO2




91015003






doiorg105194tc-8-303-2014





year-2007-2008











101175JCLI-D-13-000141







101002qj49706226601






Printer 28 pp








1520-0469(1975)0320003TEODTC20CO2




SCOAGC23CO2











101029TR027i003p00324




101029TR031i002p00174





















doiorg1010800043167219589925043




















doiorg101175MWR-D-13-003821











jpolar201802001
















101002qj3123



101038328051a0








qj49708134710





101007s00382-011-1196-9





2000JC000705






164 httpsdoiorg101002qj49708235202







s00382-013-1964-9






1011751520-0442(2003)0162078LIVIAM20CO2









1520-0469(1960)0170489TACIS20CO2


Francis 1272 pp









1748-9326aa7def




101175JCLI32531







doiorg1011751520-0469(1960)0170575STCATA20CO2

















1520-0450(1994)0330948AORFAC20CO2









103402tellusav24i110615










TAFZAS20CO2






1011751520-0493(1987)1150444TATF20CO2




1010881748-932693035008








1011751520-0442(2004)0170616CRFOTA20CO2




















1010292009GL039810



2012GL054259

















httpsdoiorg101016S0065-2687(08)60170-3




101175MWR-D-16-03331





doiorg101038321755a0















10 125005 httpsdoiorg1010881748-93261012125005












doiorg101175JCLI-D-12-006961








doiorg1010800004697319719648324










arctic3995











2889 httpsdoiorg1010022013JD020316





2008JAMC18451




acp-14-2823-2014




JCLI-D-15-06511












334 pp










1011751520-0477(2002)0830255SHBOTA23CO2





172756405781813302




THYOIM20CO2















doiorg1010291998JD200076





1010292002EO000167










1011751520-0442(1998)0113030ACRTAI20CO2



103189172756401781818671







101038srep02039



















273ndash299
























101002grl50190
















































































































































































































1958 to 2010 (Bromwich et al 2013 2014)





























































































Northwest)































































































full_report2017pdf]



















































































continent















































































Force base











f Evolving thought























(Jones 1987)



























































































































Phillips 1956)





















































































































































































































































































Weather Watch





































e Arctic clouds




















































































































































































































































































ranges






























SYSTEM

















































































































both polar regions
















NCAR)








































































manuscript

APPENDIX










































observation period




































































































































































f SEARCH (2010s)









































REFERENCES





Rep (Part II) 53 pp









2011BAMS32181













doiorg101002wcc337




















Studley Co 40 pp









1010022017GL075841



























doiorg1011751520-0442(2004)0173415PMSOTW20CO2











j1600-0870201100537x








ngeo2016



BAMS-D-16-02151


29ndash31





1010881748-9326102025003



92 (4) 429ndash522





264 httpsdoiorg101080070559002013798582











JCLI-D-15-07751









doiorg101175MWR-D-11-001821





2012GL053385






doiorg101002qj776



JCLI-D-14-004471







JCLI-D-17-02961











1520-0442(1996)0091731OOACAR20CO2




nyp33433000204663

















doiorg1010292018GL077092











1011751520-0469(1945)0020135SMAOTG20CO2



101063PT32449




doiorg101175MWR-D-12-000911



















315207a0



































101002qj2401



101175JAS-33531



2001JD001526



(1960)0170036TDCOTA20CO2



doiorg101002qj49708636802














[154MWIA]20CO2










TGGA20CO2




doiorg101007s00382-012-1512-z



86961989tb07053x











doiorg1011751520-0493(1922)50589aTCA20CO2






BF01054476




BAMS-D-14-002461




1011751520-0477(1992)0731824ISMSAF20CO2










ASAIW20CO2




91015003






doiorg105194tc-8-303-2014





year-2007-2008











101175JCLI-D-13-000141







101002qj49706226601






Printer 28 pp








1520-0469(1975)0320003TEODTC20CO2




SCOAGC23CO2











101029TR027i003p00324




101029TR031i002p00174





















doiorg1010800043167219589925043




















doiorg101175MWR-D-13-003821











jpolar201802001
















101002qj3123



101038328051a0








qj49708134710





101007s00382-011-1196-9





2000JC000705






164 httpsdoiorg101002qj49708235202







s00382-013-1964-9






1011751520-0442(2003)0162078LIVIAM20CO2









1520-0469(1960)0170489TACIS20CO2


Francis 1272 pp









1748-9326aa7def




101175JCLI32531







doiorg1011751520-0469(1960)0170575STCATA20CO2

















1520-0450(1994)0330948AORFAC20CO2









103402tellusav24i110615










TAFZAS20CO2






1011751520-0493(1987)1150444TATF20CO2




1010881748-932693035008








1011751520-0442(2004)0170616CRFOTA20CO2




















1010292009GL039810



2012GL054259

















httpsdoiorg101016S0065-2687(08)60170-3




101175MWR-D-16-03331





doiorg101038321755a0















10 125005 httpsdoiorg1010881748-93261012125005












doiorg101175JCLI-D-12-006961








doiorg1010800004697319719648324










arctic3995











2889 httpsdoiorg1010022013JD020316





2008JAMC18451




acp-14-2823-2014




JCLI-D-15-06511












334 pp










1011751520-0477(2002)0830255SHBOTA23CO2





172756405781813302




THYOIM20CO2















doiorg1010291998JD200076





1010292002EO000167










1011751520-0442(1998)0113030ACRTAI20CO2



103189172756401781818671







101038srep02039



















273ndash299
























101002grl50190

























































































































































































1958 to 2010 (Bromwich et al 2013 2014)





























































































Northwest)































































































full_report2017pdf]



















































































continent















































































Force base











f Evolving thought























(Jones 1987)



























































































































Phillips 1956)





















































































































































































































































































Weather Watch





































e Arctic clouds




















































































































































































































































































ranges






























SYSTEM

















































































































both polar regions
















NCAR)








































































manuscript

APPENDIX










































observation period




































































































































































f SEARCH (2010s)









































REFERENCES





Rep (Part II) 53 pp









2011BAMS32181













doiorg101002wcc337




















Studley Co 40 pp









1010022017GL075841



























doiorg1011751520-0442(2004)0173415PMSOTW20CO2











j1600-0870201100537x








ngeo2016



BAMS-D-16-02151


29ndash31





1010881748-9326102025003



92 (4) 429ndash522





264 httpsdoiorg101080070559002013798582











JCLI-D-15-07751









doiorg101175MWR-D-11-001821





2012GL053385






doiorg101002qj776



JCLI-D-14-004471







JCLI-D-17-02961











1520-0442(1996)0091731OOACAR20CO2




nyp33433000204663

















doiorg1010292018GL077092











1011751520-0469(1945)0020135SMAOTG20CO2



101063PT32449




doiorg101175MWR-D-12-000911



















315207a0



































101002qj2401



101175JAS-33531



2001JD001526



(1960)0170036TDCOTA20CO2



doiorg101002qj49708636802














[154MWIA]20CO2










TGGA20CO2




doiorg101007s00382-012-1512-z



86961989tb07053x











doiorg1011751520-0493(1922)50589aTCA20CO2






BF01054476




BAMS-D-14-002461




1011751520-0477(1992)0731824ISMSAF20CO2










ASAIW20CO2




91015003






doiorg105194tc-8-303-2014





year-2007-2008











101175JCLI-D-13-000141







101002qj49706226601






Printer 28 pp








1520-0469(1975)0320003TEODTC20CO2




SCOAGC23CO2











101029TR027i003p00324




101029TR031i002p00174





















doiorg1010800043167219589925043




















doiorg101175MWR-D-13-003821











jpolar201802001
















101002qj3123



101038328051a0








qj49708134710





101007s00382-011-1196-9





2000JC000705






164 httpsdoiorg101002qj49708235202







s00382-013-1964-9






1011751520-0442(2003)0162078LIVIAM20CO2









1520-0469(1960)0170489TACIS20CO2


Francis 1272 pp









1748-9326aa7def




101175JCLI32531







doiorg1011751520-0469(1960)0170575STCATA20CO2

















1520-0450(1994)0330948AORFAC20CO2









103402tellusav24i110615










TAFZAS20CO2






1011751520-0493(1987)1150444TATF20CO2




1010881748-932693035008








1011751520-0442(2004)0170616CRFOTA20CO2




















1010292009GL039810



2012GL054259

















httpsdoiorg101016S0065-2687(08)60170-3




101175MWR-D-16-03331





doiorg101038321755a0















10 125005 httpsdoiorg1010881748-93261012125005












doiorg101175JCLI-D-12-006961








doiorg1010800004697319719648324










arctic3995











2889 httpsdoiorg1010022013JD020316





2008JAMC18451




acp-14-2823-2014




JCLI-D-15-06511












334 pp










1011751520-0477(2002)0830255SHBOTA23CO2





172756405781813302




THYOIM20CO2















doiorg1010291998JD200076





1010292002EO000167










1011751520-0442(1998)0113030ACRTAI20CO2



103189172756401781818671







101038srep02039



















273ndash299
























101002grl50190












































































































































1958 to 2010 (Bromwich et al 2013 2014)





























































































Northwest)































































































full_report2017pdf]



















































































continent















































































Force base











f Evolving thought























(Jones 1987)



























































































































Phillips 1956)





















































































































































































































































































Weather Watch





































e Arctic clouds




















































































































































































































































































ranges






























SYSTEM

















































































































both polar regions
















NCAR)








































































manuscript

APPENDIX










































observation period




































































































































































f SEARCH (2010s)









































REFERENCES





Rep (Part II) 53 pp









2011BAMS32181













doiorg101002wcc337




















Studley Co 40 pp









1010022017GL075841



























doiorg1011751520-0442(2004)0173415PMSOTW20CO2











j1600-0870201100537x








ngeo2016



BAMS-D-16-02151


29ndash31





1010881748-9326102025003



92 (4) 429ndash522





264 httpsdoiorg101080070559002013798582











JCLI-D-15-07751









doiorg101175MWR-D-11-001821





2012GL053385






doiorg101002qj776



JCLI-D-14-004471







JCLI-D-17-02961











1520-0442(1996)0091731OOACAR20CO2




nyp33433000204663

















doiorg1010292018GL077092











1011751520-0469(1945)0020135SMAOTG20CO2



101063PT32449




doiorg101175MWR-D-12-000911



















315207a0



































101002qj2401



101175JAS-33531



2001JD001526



(1960)0170036TDCOTA20CO2



doiorg101002qj49708636802














[154MWIA]20CO2










TGGA20CO2




doiorg101007s00382-012-1512-z



86961989tb07053x











doiorg1011751520-0493(1922)50589aTCA20CO2






BF01054476




BAMS-D-14-002461




1011751520-0477(1992)0731824ISMSAF20CO2










ASAIW20CO2




91015003






doiorg105194tc-8-303-2014





year-2007-2008











101175JCLI-D-13-000141







101002qj49706226601






Printer 28 pp








1520-0469(1975)0320003TEODTC20CO2




SCOAGC23CO2











101029TR027i003p00324




101029TR031i002p00174





















doiorg1010800043167219589925043




















doiorg101175MWR-D-13-003821











jpolar201802001
















101002qj3123



101038328051a0








qj49708134710





101007s00382-011-1196-9





2000JC000705






164 httpsdoiorg101002qj49708235202







s00382-013-1964-9






1011751520-0442(2003)0162078LIVIAM20CO2









1520-0469(1960)0170489TACIS20CO2


Francis 1272 pp









1748-9326aa7def




101175JCLI32531







doiorg1011751520-0469(1960)0170575STCATA20CO2

















1520-0450(1994)0330948AORFAC20CO2









103402tellusav24i110615










TAFZAS20CO2






1011751520-0493(1987)1150444TATF20CO2




1010881748-932693035008








1011751520-0442(2004)0170616CRFOTA20CO2




















1010292009GL039810



2012GL054259

















httpsdoiorg101016S0065-2687(08)60170-3




101175MWR-D-16-03331





doiorg101038321755a0















10 125005 httpsdoiorg1010881748-93261012125005












doiorg101175JCLI-D-12-006961








doiorg1010800004697319719648324










arctic3995











2889 httpsdoiorg1010022013JD020316





2008JAMC18451




acp-14-2823-2014




JCLI-D-15-06511












334 pp










1011751520-0477(2002)0830255SHBOTA23CO2





172756405781813302




THYOIM20CO2















doiorg1010291998JD200076





1010292002EO000167










1011751520-0442(1998)0113030ACRTAI20CO2



103189172756401781818671







101038srep02039



















273ndash299
























101002grl50190



















































1958 to 2010 (Bromwich et al 2013 2014)





























































































Northwest)































































































full_report2017pdf]



















































































continent















































































Force base











f Evolving thought























(Jones 1987)



























































































































Phillips 1956)





















































































































































































































































































Weather Watch





































e Arctic clouds




















































































































































































































































































ranges






























SYSTEM

















































































































both polar regions
















NCAR)








































































manuscript

APPENDIX










































observation period




































































































































































f SEARCH (2010s)









































REFERENCES





Rep (Part II) 53 pp









2011BAMS32181













doiorg101002wcc337




















Studley Co 40 pp









1010022017GL075841



























doiorg1011751520-0442(2004)0173415PMSOTW20CO2











j1600-0870201100537x








ngeo2016



BAMS-D-16-02151


29ndash31





1010881748-9326102025003



92 (4) 429ndash522





264 httpsdoiorg101080070559002013798582











JCLI-D-15-07751









doiorg101175MWR-D-11-001821





2012GL053385






doiorg101002qj776



JCLI-D-14-004471







JCLI-D-17-02961











1520-0442(1996)0091731OOACAR20CO2




nyp33433000204663

















doiorg1010292018GL077092











1011751520-0469(1945)0020135SMAOTG20CO2



101063PT32449




doiorg101175MWR-D-12-000911



















315207a0



































101002qj2401



101175JAS-33531



2001JD001526



(1960)0170036TDCOTA20CO2



doiorg101002qj49708636802














[154MWIA]20CO2










TGGA20CO2




doiorg101007s00382-012-1512-z



86961989tb07053x











doiorg1011751520-0493(1922)50589aTCA20CO2






BF01054476




BAMS-D-14-002461




1011751520-0477(1992)0731824ISMSAF20CO2










ASAIW20CO2




91015003






doiorg105194tc-8-303-2014





year-2007-2008











101175JCLI-D-13-000141







101002qj49706226601






Printer 28 pp








1520-0469(1975)0320003TEODTC20CO2




SCOAGC23CO2











101029TR027i003p00324




101029TR031i002p00174





















doiorg1010800043167219589925043




















doiorg101175MWR-D-13-003821











jpolar201802001
















101002qj3123



101038328051a0








qj49708134710





101007s00382-011-1196-9





2000JC000705






164 httpsdoiorg101002qj49708235202







s00382-013-1964-9






1011751520-0442(2003)0162078LIVIAM20CO2









1520-0469(1960)0170489TACIS20CO2


Francis 1272 pp









1748-9326aa7def




101175JCLI32531







doiorg1011751520-0469(1960)0170575STCATA20CO2

















1520-0450(1994)0330948AORFAC20CO2









103402tellusav24i110615










TAFZAS20CO2






1011751520-0493(1987)1150444TATF20CO2




1010881748-932693035008








1011751520-0442(2004)0170616CRFOTA20CO2




















1010292009GL039810



2012GL054259

















httpsdoiorg101016S0065-2687(08)60170-3




101175MWR-D-16-03331





doiorg101038321755a0















10 125005 httpsdoiorg1010881748-93261012125005












doiorg101175JCLI-D-12-006961








doiorg1010800004697319719648324










arctic3995











2889 httpsdoiorg1010022013JD020316





2008JAMC18451




acp-14-2823-2014




JCLI-D-15-06511












334 pp










1011751520-0477(2002)0830255SHBOTA23CO2





172756405781813302




THYOIM20CO2















doiorg1010291998JD200076





1010292002EO000167










1011751520-0442(1998)0113030ACRTAI20CO2



103189172756401781818671







101038srep02039



















273ndash299
























101002grl50190








































Northwest)































































































full_report2017pdf]



















































































continent















































































Force base











f Evolving thought























(Jones 1987)



























































































































Phillips 1956)





















































































































































































































































































Weather Watch





































e Arctic clouds




















































































































































































































































































ranges






























SYSTEM

















































































































both polar regions
















NCAR)








































































manuscript

APPENDIX










































observation period




































































































































































f SEARCH (2010s)









































REFERENCES





Rep (Part II) 53 pp









2011BAMS32181













doiorg101002wcc337




















Studley Co 40 pp









1010022017GL075841



























doiorg1011751520-0442(2004)0173415PMSOTW20CO2











j1600-0870201100537x








ngeo2016



BAMS-D-16-02151


29ndash31





1010881748-9326102025003



92 (4) 429ndash522





264 httpsdoiorg101080070559002013798582











JCLI-D-15-07751









doiorg101175MWR-D-11-001821





2012GL053385






doiorg101002qj776



JCLI-D-14-004471







JCLI-D-17-02961











1520-0442(1996)0091731OOACAR20CO2




nyp33433000204663

















doiorg1010292018GL077092











1011751520-0469(1945)0020135SMAOTG20CO2



101063PT32449




doiorg101175MWR-D-12-000911



















315207a0



































101002qj2401



101175JAS-33531



2001JD001526



(1960)0170036TDCOTA20CO2



doiorg101002qj49708636802














[154MWIA]20CO2










TGGA20CO2




doiorg101007s00382-012-1512-z



86961989tb07053x











doiorg1011751520-0493(1922)50589aTCA20CO2






BF01054476




BAMS-D-14-002461




1011751520-0477(1992)0731824ISMSAF20CO2










ASAIW20CO2




91015003






doiorg105194tc-8-303-2014





year-2007-2008











101175JCLI-D-13-000141







101002qj49706226601






Printer 28 pp








1520-0469(1975)0320003TEODTC20CO2




SCOAGC23CO2











101029TR027i003p00324




101029TR031i002p00174





















doiorg1010800043167219589925043




















doiorg101175MWR-D-13-003821











jpolar201802001
















101002qj3123



101038328051a0








qj49708134710





101007s00382-011-1196-9





2000JC000705






164 httpsdoiorg101002qj49708235202







s00382-013-1964-9






1011751520-0442(2003)0162078LIVIAM20CO2









1520-0469(1960)0170489TACIS20CO2


Francis 1272 pp









1748-9326aa7def




101175JCLI32531







doiorg1011751520-0469(1960)0170575STCATA20CO2

















1520-0450(1994)0330948AORFAC20CO2









103402tellusav24i110615










TAFZAS20CO2






1011751520-0493(1987)1150444TATF20CO2




1010881748-932693035008








1011751520-0442(2004)0170616CRFOTA20CO2




















1010292009GL039810



2012GL054259

















httpsdoiorg101016S0065-2687(08)60170-3




101175MWR-D-16-03331





doiorg101038321755a0















10 125005 httpsdoiorg1010881748-93261012125005












doiorg101175JCLI-D-12-006961








doiorg1010800004697319719648324










arctic3995











2889 httpsdoiorg1010022013JD020316





2008JAMC18451




acp-14-2823-2014




JCLI-D-15-06511












334 pp










1011751520-0477(2002)0830255SHBOTA23CO2





172756405781813302




THYOIM20CO2















doiorg1010291998JD200076





1010292002EO000167










1011751520-0442(1998)0113030ACRTAI20CO2



103189172756401781818671







101038srep02039



















273ndash299
























101002grl50190



































































































full_report2017pdf]



















































































continent















































































Force base











f Evolving thought























(Jones 1987)



























































































































Phillips 1956)





















































































































































































































































































Weather Watch





































e Arctic clouds




















































































































































































































































































ranges






























SYSTEM

















































































































both polar regions
















NCAR)








































































manuscript

APPENDIX










































observation period




































































































































































f SEARCH (2010s)









































REFERENCES





Rep (Part II) 53 pp









2011BAMS32181













doiorg101002wcc337




















Studley Co 40 pp









1010022017GL075841



























doiorg1011751520-0442(2004)0173415PMSOTW20CO2











j1600-0870201100537x








ngeo2016



BAMS-D-16-02151


29ndash31





1010881748-9326102025003



92 (4) 429ndash522





264 httpsdoiorg101080070559002013798582











JCLI-D-15-07751









doiorg101175MWR-D-11-001821





2012GL053385






doiorg101002qj776



JCLI-D-14-004471







JCLI-D-17-02961











1520-0442(1996)0091731OOACAR20CO2




nyp33433000204663

















doiorg1010292018GL077092











1011751520-0469(1945)0020135SMAOTG20CO2



101063PT32449




doiorg101175MWR-D-12-000911



















315207a0



































101002qj2401



101175JAS-33531



2001JD001526



(1960)0170036TDCOTA20CO2



doiorg101002qj49708636802














[154MWIA]20CO2










TGGA20CO2




doiorg101007s00382-012-1512-z



86961989tb07053x











doiorg1011751520-0493(1922)50589aTCA20CO2






BF01054476




BAMS-D-14-002461




1011751520-0477(1992)0731824ISMSAF20CO2










ASAIW20CO2




91015003






doiorg105194tc-8-303-2014





year-2007-2008











101175JCLI-D-13-000141







101002qj49706226601






Printer 28 pp








1520-0469(1975)0320003TEODTC20CO2




SCOAGC23CO2











101029TR027i003p00324




101029TR031i002p00174





















doiorg1010800043167219589925043




















doiorg101175MWR-D-13-003821











jpolar201802001
















101002qj3123



101038328051a0








qj49708134710





101007s00382-011-1196-9





2000JC000705






164 httpsdoiorg101002qj49708235202







s00382-013-1964-9






1011751520-0442(2003)0162078LIVIAM20CO2









1520-0469(1960)0170489TACIS20CO2


Francis 1272 pp









1748-9326aa7def




101175JCLI32531







doiorg1011751520-0469(1960)0170575STCATA20CO2

















1520-0450(1994)0330948AORFAC20CO2









103402tellusav24i110615










TAFZAS20CO2






1011751520-0493(1987)1150444TATF20CO2




1010881748-932693035008








1011751520-0442(2004)0170616CRFOTA20CO2




















1010292009GL039810



2012GL054259

















httpsdoiorg101016S0065-2687(08)60170-3




101175MWR-D-16-03331





doiorg101038321755a0















10 125005 httpsdoiorg1010881748-93261012125005












doiorg101175JCLI-D-12-006961








doiorg1010800004697319719648324










arctic3995











2889 httpsdoiorg1010022013JD020316





2008JAMC18451




acp-14-2823-2014




JCLI-D-15-06511












334 pp










1011751520-0477(2002)0830255SHBOTA23CO2





172756405781813302




THYOIM20CO2















doiorg1010291998JD200076





1010292002EO000167










1011751520-0442(1998)0113030ACRTAI20CO2



103189172756401781818671







101038srep02039



















273ndash299
























101002grl50190























































































continent















































































Force base











f Evolving thought























(Jones 1987)



























































































































Phillips 1956)





















































































































































































































































































Weather Watch





































e Arctic clouds




















































































































































































































































































ranges






























SYSTEM

















































































































both polar regions
















NCAR)








































































manuscript

APPENDIX










































observation period




































































































































































f SEARCH (2010s)









































REFERENCES





Rep (Part II) 53 pp









2011BAMS32181













doiorg101002wcc337




















Studley Co 40 pp









1010022017GL075841



























doiorg1011751520-0442(2004)0173415PMSOTW20CO2











j1600-0870201100537x








ngeo2016



BAMS-D-16-02151


29ndash31





1010881748-9326102025003



92 (4) 429ndash522





264 httpsdoiorg101080070559002013798582











JCLI-D-15-07751









doiorg101175MWR-D-11-001821





2012GL053385






doiorg101002qj776



JCLI-D-14-004471







JCLI-D-17-02961











1520-0442(1996)0091731OOACAR20CO2




nyp33433000204663

















doiorg1010292018GL077092











1011751520-0469(1945)0020135SMAOTG20CO2



101063PT32449




doiorg101175MWR-D-12-000911



















315207a0



































101002qj2401



101175JAS-33531



2001JD001526



(1960)0170036TDCOTA20CO2



doiorg101002qj49708636802














[154MWIA]20CO2










TGGA20CO2




doiorg101007s00382-012-1512-z



86961989tb07053x











doiorg1011751520-0493(1922)50589aTCA20CO2






BF01054476




BAMS-D-14-002461




1011751520-0477(1992)0731824ISMSAF20CO2










ASAIW20CO2




91015003






doiorg105194tc-8-303-2014





year-2007-2008











101175JCLI-D-13-000141







101002qj49706226601






Printer 28 pp








1520-0469(1975)0320003TEODTC20CO2




SCOAGC23CO2











101029TR027i003p00324




101029TR031i002p00174





















doiorg1010800043167219589925043




















doiorg101175MWR-D-13-003821











jpolar201802001
















101002qj3123



101038328051a0








qj49708134710





101007s00382-011-1196-9





2000JC000705






164 httpsdoiorg101002qj49708235202







s00382-013-1964-9






1011751520-0442(2003)0162078LIVIAM20CO2









1520-0469(1960)0170489TACIS20CO2


Francis 1272 pp









1748-9326aa7def




101175JCLI32531







doiorg1011751520-0469(1960)0170575STCATA20CO2

















1520-0450(1994)0330948AORFAC20CO2









103402tellusav24i110615










TAFZAS20CO2






1011751520-0493(1987)1150444TATF20CO2




1010881748-932693035008








1011751520-0442(2004)0170616CRFOTA20CO2




















1010292009GL039810



2012GL054259

















httpsdoiorg101016S0065-2687(08)60170-3




101175MWR-D-16-03331





doiorg101038321755a0















10 125005 httpsdoiorg1010881748-93261012125005












doiorg101175JCLI-D-12-006961








doiorg1010800004697319719648324










arctic3995











2889 httpsdoiorg1010022013JD020316





2008JAMC18451




acp-14-2823-2014




JCLI-D-15-06511












334 pp










1011751520-0477(2002)0830255SHBOTA23CO2





172756405781813302




THYOIM20CO2















doiorg1010291998JD200076





1010292002EO000167










1011751520-0442(1998)0113030ACRTAI20CO2



103189172756401781818671







101038srep02039



















273ndash299
























101002grl50190


































































Force base











f Evolving thought























(Jones 1987)



























































































































Phillips 1956)





















































































































































































































































































Weather Watch





































e Arctic clouds




















































































































































































































































































ranges






























SYSTEM

















































































































both polar regions
















NCAR)








































































manuscript

APPENDIX










































observation period




































































































































































f SEARCH (2010s)









































REFERENCES





Rep (Part II) 53 pp









2011BAMS32181













doiorg101002wcc337




















Studley Co 40 pp









1010022017GL075841



























doiorg1011751520-0442(2004)0173415PMSOTW20CO2











j1600-0870201100537x








ngeo2016



BAMS-D-16-02151


29ndash31





1010881748-9326102025003



92 (4) 429ndash522





264 httpsdoiorg101080070559002013798582











JCLI-D-15-07751









doiorg101175MWR-D-11-001821





2012GL053385






doiorg101002qj776



JCLI-D-14-004471







JCLI-D-17-02961











1520-0442(1996)0091731OOACAR20CO2




nyp33433000204663

















doiorg1010292018GL077092











1011751520-0469(1945)0020135SMAOTG20CO2



101063PT32449




doiorg101175MWR-D-12-000911



















315207a0



































101002qj2401



101175JAS-33531



2001JD001526



(1960)0170036TDCOTA20CO2



doiorg101002qj49708636802














[154MWIA]20CO2










TGGA20CO2




doiorg101007s00382-012-1512-z



86961989tb07053x











doiorg1011751520-0493(1922)50589aTCA20CO2






BF01054476




BAMS-D-14-002461




1011751520-0477(1992)0731824ISMSAF20CO2










ASAIW20CO2




91015003






doiorg105194tc-8-303-2014





year-2007-2008











101175JCLI-D-13-000141







101002qj49706226601






Printer 28 pp








1520-0469(1975)0320003TEODTC20CO2




SCOAGC23CO2











101029TR027i003p00324




101029TR031i002p00174





















doiorg1010800043167219589925043




















doiorg101175MWR-D-13-003821











jpolar201802001
















101002qj3123



101038328051a0








qj49708134710





101007s00382-011-1196-9





2000JC000705






164 httpsdoiorg101002qj49708235202







s00382-013-1964-9






1011751520-0442(2003)0162078LIVIAM20CO2









1520-0469(1960)0170489TACIS20CO2


Francis 1272 pp









1748-9326aa7def




101175JCLI32531







doiorg1011751520-0469(1960)0170575STCATA20CO2

















1520-0450(1994)0330948AORFAC20CO2









103402tellusav24i110615










TAFZAS20CO2






1011751520-0493(1987)1150444TATF20CO2




1010881748-932693035008








1011751520-0442(2004)0170616CRFOTA20CO2




















1010292009GL039810



2012GL054259

















httpsdoiorg101016S0065-2687(08)60170-3




101175MWR-D-16-03331





doiorg101038321755a0















10 125005 httpsdoiorg1010881748-93261012125005












doiorg101175JCLI-D-12-006961








doiorg1010800004697319719648324










arctic3995











2889 httpsdoiorg1010022013JD020316





2008JAMC18451




acp-14-2823-2014




JCLI-D-15-06511












334 pp










1011751520-0477(2002)0830255SHBOTA23CO2





172756405781813302




THYOIM20CO2















doiorg1010291998JD200076





1010292002EO000167










1011751520-0442(1998)0113030ACRTAI20CO2



103189172756401781818671







101038srep02039



















273ndash299
























101002grl50190



























































































































Phillips 1956)





















































































































































































































































































Weather Watch





































e Arctic clouds




















































































































































































































































































ranges






























SYSTEM

















































































































both polar regions
















NCAR)








































































manuscript

APPENDIX










































observation period




































































































































































f SEARCH (2010s)









































REFERENCES





Rep (Part II) 53 pp









2011BAMS32181













doiorg101002wcc337




















Studley Co 40 pp









1010022017GL075841



























doiorg1011751520-0442(2004)0173415PMSOTW20CO2











j1600-0870201100537x








ngeo2016



BAMS-D-16-02151


29ndash31





1010881748-9326102025003



92 (4) 429ndash522





264 httpsdoiorg101080070559002013798582











JCLI-D-15-07751









doiorg101175MWR-D-11-001821





2012GL053385






doiorg101002qj776



JCLI-D-14-004471







JCLI-D-17-02961











1520-0442(1996)0091731OOACAR20CO2




nyp33433000204663

















doiorg1010292018GL077092











1011751520-0469(1945)0020135SMAOTG20CO2



101063PT32449




doiorg101175MWR-D-12-000911



















315207a0



































101002qj2401



101175JAS-33531



2001JD001526



(1960)0170036TDCOTA20CO2



doiorg101002qj49708636802














[154MWIA]20CO2










TGGA20CO2




doiorg101007s00382-012-1512-z



86961989tb07053x











doiorg1011751520-0493(1922)50589aTCA20CO2






BF01054476




BAMS-D-14-002461




1011751520-0477(1992)0731824ISMSAF20CO2










ASAIW20CO2




91015003






doiorg105194tc-8-303-2014





year-2007-2008











101175JCLI-D-13-000141







101002qj49706226601






Printer 28 pp








1520-0469(1975)0320003TEODTC20CO2




SCOAGC23CO2











101029TR027i003p00324




101029TR031i002p00174





















doiorg1010800043167219589925043




















doiorg101175MWR-D-13-003821











jpolar201802001
















101002qj3123



101038328051a0








qj49708134710





101007s00382-011-1196-9





2000JC000705






164 httpsdoiorg101002qj49708235202







s00382-013-1964-9






1011751520-0442(2003)0162078LIVIAM20CO2









1520-0469(1960)0170489TACIS20CO2


Francis 1272 pp









1748-9326aa7def




101175JCLI32531







doiorg1011751520-0469(1960)0170575STCATA20CO2

















1520-0450(1994)0330948AORFAC20CO2









103402tellusav24i110615










TAFZAS20CO2






1011751520-0493(1987)1150444TATF20CO2




1010881748-932693035008








1011751520-0442(2004)0170616CRFOTA20CO2




















1010292009GL039810



2012GL054259

















httpsdoiorg101016S0065-2687(08)60170-3




101175MWR-D-16-03331





doiorg101038321755a0















10 125005 httpsdoiorg1010881748-93261012125005












doiorg101175JCLI-D-12-006961








doiorg1010800004697319719648324










arctic3995











2889 httpsdoiorg1010022013JD020316





2008JAMC18451




acp-14-2823-2014




JCLI-D-15-06511












334 pp










1011751520-0477(2002)0830255SHBOTA23CO2





172756405781813302




THYOIM20CO2















doiorg1010291998JD200076





1010292002EO000167










1011751520-0442(1998)0113030ACRTAI20CO2



103189172756401781818671







101038srep02039



















273ndash299
























101002grl50190





















































































Phillips 1956)





















































































































































































































































































Weather Watch





































e Arctic clouds




















































































































































































































































































ranges






























SYSTEM

















































































































both polar regions
















NCAR)








































































manuscript

APPENDIX










































observation period




































































































































































f SEARCH (2010s)









































REFERENCES





Rep (Part II) 53 pp









2011BAMS32181













doiorg101002wcc337




















Studley Co 40 pp









1010022017GL075841



























doiorg1011751520-0442(2004)0173415PMSOTW20CO2











j1600-0870201100537x








ngeo2016



BAMS-D-16-02151


29ndash31





1010881748-9326102025003



92 (4) 429ndash522





264 httpsdoiorg101080070559002013798582











JCLI-D-15-07751









doiorg101175MWR-D-11-001821





2012GL053385






doiorg101002qj776



JCLI-D-14-004471







JCLI-D-17-02961











1520-0442(1996)0091731OOACAR20CO2




nyp33433000204663

















doiorg1010292018GL077092











1011751520-0469(1945)0020135SMAOTG20CO2



101063PT32449




doiorg101175MWR-D-12-000911



















315207a0



































101002qj2401



101175JAS-33531



2001JD001526



(1960)0170036TDCOTA20CO2



doiorg101002qj49708636802














[154MWIA]20CO2










TGGA20CO2




doiorg101007s00382-012-1512-z



86961989tb07053x











doiorg1011751520-0493(1922)50589aTCA20CO2






BF01054476




BAMS-D-14-002461




1011751520-0477(1992)0731824ISMSAF20CO2










ASAIW20CO2




91015003






doiorg105194tc-8-303-2014





year-2007-2008











101175JCLI-D-13-000141







101002qj49706226601






Printer 28 pp








1520-0469(1975)0320003TEODTC20CO2




SCOAGC23CO2











101029TR027i003p00324




101029TR031i002p00174





















doiorg1010800043167219589925043




















doiorg101175MWR-D-13-003821











jpolar201802001
















101002qj3123



101038328051a0








qj49708134710





101007s00382-011-1196-9





2000JC000705






164 httpsdoiorg101002qj49708235202







s00382-013-1964-9






1011751520-0442(2003)0162078LIVIAM20CO2









1520-0469(1960)0170489TACIS20CO2


Francis 1272 pp









1748-9326aa7def




101175JCLI32531







doiorg1011751520-0469(1960)0170575STCATA20CO2

















1520-0450(1994)0330948AORFAC20CO2









103402tellusav24i110615










TAFZAS20CO2






1011751520-0493(1987)1150444TATF20CO2




1010881748-932693035008








1011751520-0442(2004)0170616CRFOTA20CO2




















1010292009GL039810



2012GL054259

















httpsdoiorg101016S0065-2687(08)60170-3




101175MWR-D-16-03331





doiorg101038321755a0















10 125005 httpsdoiorg1010881748-93261012125005












doiorg101175JCLI-D-12-006961








doiorg1010800004697319719648324










arctic3995











2889 httpsdoiorg1010022013JD020316





2008JAMC18451




acp-14-2823-2014




JCLI-D-15-06511












334 pp










1011751520-0477(2002)0830255SHBOTA23CO2





172756405781813302




THYOIM20CO2















doiorg1010291998JD200076





1010292002EO000167










1011751520-0442(1998)0113030ACRTAI20CO2



103189172756401781818671







101038srep02039



















273ndash299
























101002grl50190
































































































































































































































































Weather Watch





































e Arctic clouds




















































































































































































































































































ranges






























SYSTEM

















































































































both polar regions
















NCAR)








































































manuscript

APPENDIX










































observation period




































































































































































f SEARCH (2010s)









































REFERENCES





Rep (Part II) 53 pp









2011BAMS32181













doiorg101002wcc337




















Studley Co 40 pp









1010022017GL075841



























doiorg1011751520-0442(2004)0173415PMSOTW20CO2











j1600-0870201100537x








ngeo2016



BAMS-D-16-02151


29ndash31





1010881748-9326102025003



92 (4) 429ndash522





264 httpsdoiorg101080070559002013798582











JCLI-D-15-07751









doiorg101175MWR-D-11-001821





2012GL053385






doiorg101002qj776



JCLI-D-14-004471







JCLI-D-17-02961











1520-0442(1996)0091731OOACAR20CO2




nyp33433000204663

















doiorg1010292018GL077092











1011751520-0469(1945)0020135SMAOTG20CO2



101063PT32449




doiorg101175MWR-D-12-000911



















315207a0



































101002qj2401



101175JAS-33531



2001JD001526



(1960)0170036TDCOTA20CO2



doiorg101002qj49708636802














[154MWIA]20CO2










TGGA20CO2




doiorg101007s00382-012-1512-z



86961989tb07053x











doiorg1011751520-0493(1922)50589aTCA20CO2






BF01054476




BAMS-D-14-002461




1011751520-0477(1992)0731824ISMSAF20CO2










ASAIW20CO2




91015003






doiorg105194tc-8-303-2014





year-2007-2008











101175JCLI-D-13-000141







101002qj49706226601






Printer 28 pp








1520-0469(1975)0320003TEODTC20CO2




SCOAGC23CO2











101029TR027i003p00324




101029TR031i002p00174





















doiorg1010800043167219589925043




















doiorg101175MWR-D-13-003821











jpolar201802001
















101002qj3123



101038328051a0








qj49708134710





101007s00382-011-1196-9





2000JC000705






164 httpsdoiorg101002qj49708235202







s00382-013-1964-9






1011751520-0442(2003)0162078LIVIAM20CO2









1520-0469(1960)0170489TACIS20CO2


Francis 1272 pp









1748-9326aa7def




101175JCLI32531







doiorg1011751520-0469(1960)0170575STCATA20CO2

















1520-0450(1994)0330948AORFAC20CO2









103402tellusav24i110615










TAFZAS20CO2






1011751520-0493(1987)1150444TATF20CO2




1010881748-932693035008








1011751520-0442(2004)0170616CRFOTA20CO2




















1010292009GL039810



2012GL054259

















httpsdoiorg101016S0065-2687(08)60170-3




101175MWR-D-16-03331





doiorg101038321755a0















10 125005 httpsdoiorg1010881748-93261012125005












doiorg101175JCLI-D-12-006961








doiorg1010800004697319719648324










arctic3995











2889 httpsdoiorg1010022013JD020316





2008JAMC18451




acp-14-2823-2014




JCLI-D-15-06511












334 pp










1011751520-0477(2002)0830255SHBOTA23CO2





172756405781813302




THYOIM20CO2















doiorg1010291998JD200076





1010292002EO000167










1011751520-0442(1998)0113030ACRTAI20CO2



103189172756401781818671







101038srep02039



















273ndash299
























101002grl50190




























































































































































































































Weather Watch





































e Arctic clouds




















































































































































































































































































ranges






























SYSTEM

















































































































both polar regions
















NCAR)








































































manuscript

APPENDIX










































observation period




































































































































































f SEARCH (2010s)









































REFERENCES





Rep (Part II) 53 pp









2011BAMS32181













doiorg101002wcc337




















Studley Co 40 pp









1010022017GL075841



























doiorg1011751520-0442(2004)0173415PMSOTW20CO2











j1600-0870201100537x








ngeo2016



BAMS-D-16-02151


29ndash31





1010881748-9326102025003



92 (4) 429ndash522





264 httpsdoiorg101080070559002013798582











JCLI-D-15-07751









doiorg101175MWR-D-11-001821





2012GL053385






doiorg101002qj776



JCLI-D-14-004471







JCLI-D-17-02961











1520-0442(1996)0091731OOACAR20CO2




nyp33433000204663

















doiorg1010292018GL077092











1011751520-0469(1945)0020135SMAOTG20CO2



101063PT32449




doiorg101175MWR-D-12-000911



















315207a0



































101002qj2401



101175JAS-33531



2001JD001526



(1960)0170036TDCOTA20CO2



doiorg101002qj49708636802














[154MWIA]20CO2










TGGA20CO2




doiorg101007s00382-012-1512-z



86961989tb07053x











doiorg1011751520-0493(1922)50589aTCA20CO2






BF01054476




BAMS-D-14-002461




1011751520-0477(1992)0731824ISMSAF20CO2










ASAIW20CO2




91015003






doiorg105194tc-8-303-2014





year-2007-2008











101175JCLI-D-13-000141







101002qj49706226601






Printer 28 pp








1520-0469(1975)0320003TEODTC20CO2




SCOAGC23CO2











101029TR027i003p00324




101029TR031i002p00174





















doiorg1010800043167219589925043




















doiorg101175MWR-D-13-003821











jpolar201802001
















101002qj3123



101038328051a0








qj49708134710





101007s00382-011-1196-9





2000JC000705






164 httpsdoiorg101002qj49708235202







s00382-013-1964-9






1011751520-0442(2003)0162078LIVIAM20CO2









1520-0469(1960)0170489TACIS20CO2


Francis 1272 pp









1748-9326aa7def




101175JCLI32531







doiorg1011751520-0469(1960)0170575STCATA20CO2

















1520-0450(1994)0330948AORFAC20CO2









103402tellusav24i110615










TAFZAS20CO2






1011751520-0493(1987)1150444TATF20CO2




1010881748-932693035008








1011751520-0442(2004)0170616CRFOTA20CO2




















1010292009GL039810



2012GL054259

















httpsdoiorg101016S0065-2687(08)60170-3




101175MWR-D-16-03331





doiorg101038321755a0















10 125005 httpsdoiorg1010881748-93261012125005












doiorg101175JCLI-D-12-006961








doiorg1010800004697319719648324










arctic3995











2889 httpsdoiorg1010022013JD020316





2008JAMC18451




acp-14-2823-2014




JCLI-D-15-06511












334 pp










1011751520-0477(2002)0830255SHBOTA23CO2





172756405781813302




THYOIM20CO2















doiorg1010291998JD200076





1010292002EO000167










1011751520-0442(1998)0113030ACRTAI20CO2



103189172756401781818671







101038srep02039



















273ndash299
























101002grl50190























































































































Weather Watch





































e Arctic clouds




















































































































































































































































































ranges






























SYSTEM

















































































































both polar regions
















NCAR)








































































manuscript

APPENDIX










































observation period




































































































































































f SEARCH (2010s)









































REFERENCES





Rep (Part II) 53 pp









2011BAMS32181













doiorg101002wcc337




















Studley Co 40 pp









1010022017GL075841



























doiorg1011751520-0442(2004)0173415PMSOTW20CO2











j1600-0870201100537x








ngeo2016



BAMS-D-16-02151


29ndash31





1010881748-9326102025003



92 (4) 429ndash522





264 httpsdoiorg101080070559002013798582











JCLI-D-15-07751









doiorg101175MWR-D-11-001821





2012GL053385






doiorg101002qj776



JCLI-D-14-004471







JCLI-D-17-02961











1520-0442(1996)0091731OOACAR20CO2




nyp33433000204663

















doiorg1010292018GL077092











1011751520-0469(1945)0020135SMAOTG20CO2



101063PT32449




doiorg101175MWR-D-12-000911



















315207a0



































101002qj2401



101175JAS-33531



2001JD001526



(1960)0170036TDCOTA20CO2



doiorg101002qj49708636802














[154MWIA]20CO2










TGGA20CO2




doiorg101007s00382-012-1512-z



86961989tb07053x











doiorg1011751520-0493(1922)50589aTCA20CO2






BF01054476




BAMS-D-14-002461




1011751520-0477(1992)0731824ISMSAF20CO2










ASAIW20CO2




91015003






doiorg105194tc-8-303-2014





year-2007-2008











101175JCLI-D-13-000141







101002qj49706226601






Printer 28 pp








1520-0469(1975)0320003TEODTC20CO2




SCOAGC23CO2











101029TR027i003p00324




101029TR031i002p00174





















doiorg1010800043167219589925043




















doiorg101175MWR-D-13-003821











jpolar201802001
















101002qj3123



101038328051a0








qj49708134710





101007s00382-011-1196-9





2000JC000705






164 httpsdoiorg101002qj49708235202







s00382-013-1964-9






1011751520-0442(2003)0162078LIVIAM20CO2









1520-0469(1960)0170489TACIS20CO2


Francis 1272 pp









1748-9326aa7def




101175JCLI32531







doiorg1011751520-0469(1960)0170575STCATA20CO2

















1520-0450(1994)0330948AORFAC20CO2









103402tellusav24i110615










TAFZAS20CO2






1011751520-0493(1987)1150444TATF20CO2




1010881748-932693035008








1011751520-0442(2004)0170616CRFOTA20CO2




















1010292009GL039810



2012GL054259

















httpsdoiorg101016S0065-2687(08)60170-3




101175MWR-D-16-03331





doiorg101038321755a0















10 125005 httpsdoiorg1010881748-93261012125005












doiorg101175JCLI-D-12-006961








doiorg1010800004697319719648324










arctic3995











2889 httpsdoiorg1010022013JD020316





2008JAMC18451




acp-14-2823-2014




JCLI-D-15-06511












334 pp










1011751520-0477(2002)0830255SHBOTA23CO2





172756405781813302




THYOIM20CO2















doiorg1010291998JD200076





1010292002EO000167










1011751520-0442(1998)0113030ACRTAI20CO2



103189172756401781818671







101038srep02039



















273ndash299
























101002grl50190


























































Weather Watch





































e Arctic clouds




















































































































































































































































































ranges






























SYSTEM

















































































































both polar regions
















NCAR)








































































manuscript

APPENDIX










































observation period




































































































































































f SEARCH (2010s)









































REFERENCES





Rep (Part II) 53 pp









2011BAMS32181













doiorg101002wcc337




















Studley Co 40 pp









1010022017GL075841



























doiorg1011751520-0442(2004)0173415PMSOTW20CO2











j1600-0870201100537x








ngeo2016



BAMS-D-16-02151


29ndash31





1010881748-9326102025003



92 (4) 429ndash522





264 httpsdoiorg101080070559002013798582











JCLI-D-15-07751









doiorg101175MWR-D-11-001821





2012GL053385






doiorg101002qj776



JCLI-D-14-004471







JCLI-D-17-02961











1520-0442(1996)0091731OOACAR20CO2




nyp33433000204663

















doiorg1010292018GL077092











1011751520-0469(1945)0020135SMAOTG20CO2



101063PT32449




doiorg101175MWR-D-12-000911



















315207a0



































101002qj2401



101175JAS-33531



2001JD001526



(1960)0170036TDCOTA20CO2



doiorg101002qj49708636802














[154MWIA]20CO2










TGGA20CO2




doiorg101007s00382-012-1512-z



86961989tb07053x











doiorg1011751520-0493(1922)50589aTCA20CO2






BF01054476




BAMS-D-14-002461




1011751520-0477(1992)0731824ISMSAF20CO2










ASAIW20CO2




91015003






doiorg105194tc-8-303-2014





year-2007-2008











101175JCLI-D-13-000141







101002qj49706226601






Printer 28 pp








1520-0469(1975)0320003TEODTC20CO2




SCOAGC23CO2











101029TR027i003p00324




101029TR031i002p00174





















doiorg1010800043167219589925043




















doiorg101175MWR-D-13-003821











jpolar201802001
















101002qj3123



101038328051a0








qj49708134710





101007s00382-011-1196-9





2000JC000705






164 httpsdoiorg101002qj49708235202







s00382-013-1964-9






1011751520-0442(2003)0162078LIVIAM20CO2









1520-0469(1960)0170489TACIS20CO2


Francis 1272 pp









1748-9326aa7def




101175JCLI32531







doiorg1011751520-0469(1960)0170575STCATA20CO2

















1520-0450(1994)0330948AORFAC20CO2









103402tellusav24i110615










TAFZAS20CO2






1011751520-0493(1987)1150444TATF20CO2




1010881748-932693035008








1011751520-0442(2004)0170616CRFOTA20CO2




















1010292009GL039810



2012GL054259

















httpsdoiorg101016S0065-2687(08)60170-3




101175MWR-D-16-03331





doiorg101038321755a0















10 125005 httpsdoiorg1010881748-93261012125005












doiorg101175JCLI-D-12-006961








doiorg1010800004697319719648324










arctic3995











2889 httpsdoiorg1010022013JD020316





2008JAMC18451




acp-14-2823-2014




JCLI-D-15-06511












334 pp










1011751520-0477(2002)0830255SHBOTA23CO2





172756405781813302




THYOIM20CO2















doiorg1010291998JD200076





1010292002EO000167










1011751520-0442(1998)0113030ACRTAI20CO2



103189172756401781818671







101038srep02039



















273ndash299
























101002grl50190











Weather Watch





































e Arctic clouds




















































































































































































































































































ranges






























SYSTEM

















































































































both polar regions
















NCAR)








































































manuscript

APPENDIX










































observation period




































































































































































f SEARCH (2010s)









































REFERENCES





Rep (Part II) 53 pp









2011BAMS32181













doiorg101002wcc337




















Studley Co 40 pp









1010022017GL075841



























doiorg1011751520-0442(2004)0173415PMSOTW20CO2











j1600-0870201100537x








ngeo2016



BAMS-D-16-02151


29ndash31





1010881748-9326102025003



92 (4) 429ndash522





264 httpsdoiorg101080070559002013798582











JCLI-D-15-07751









doiorg101175MWR-D-11-001821





2012GL053385






doiorg101002qj776



JCLI-D-14-004471







JCLI-D-17-02961











1520-0442(1996)0091731OOACAR20CO2




nyp33433000204663

















doiorg1010292018GL077092











1011751520-0469(1945)0020135SMAOTG20CO2



101063PT32449




doiorg101175MWR-D-12-000911



















315207a0



































101002qj2401



101175JAS-33531



2001JD001526



(1960)0170036TDCOTA20CO2



doiorg101002qj49708636802














[154MWIA]20CO2










TGGA20CO2




doiorg101007s00382-012-1512-z



86961989tb07053x











doiorg1011751520-0493(1922)50589aTCA20CO2






BF01054476




BAMS-D-14-002461




1011751520-0477(1992)0731824ISMSAF20CO2










ASAIW20CO2




91015003






doiorg105194tc-8-303-2014





year-2007-2008











101175JCLI-D-13-000141







101002qj49706226601






Printer 28 pp








1520-0469(1975)0320003TEODTC20CO2




SCOAGC23CO2











101029TR027i003p00324




101029TR031i002p00174





















doiorg1010800043167219589925043




















doiorg101175MWR-D-13-003821











jpolar201802001
















101002qj3123



101038328051a0








qj49708134710





101007s00382-011-1196-9





2000JC000705






164 httpsdoiorg101002qj49708235202







s00382-013-1964-9






1011751520-0442(2003)0162078LIVIAM20CO2









1520-0469(1960)0170489TACIS20CO2


Francis 1272 pp









1748-9326aa7def




101175JCLI32531







doiorg1011751520-0469(1960)0170575STCATA20CO2

















1520-0450(1994)0330948AORFAC20CO2









103402tellusav24i110615










TAFZAS20CO2






1011751520-0493(1987)1150444TATF20CO2




1010881748-932693035008








1011751520-0442(2004)0170616CRFOTA20CO2




















1010292009GL039810



2012GL054259

















httpsdoiorg101016S0065-2687(08)60170-3




101175MWR-D-16-03331





doiorg101038321755a0















10 125005 httpsdoiorg1010881748-93261012125005












doiorg101175JCLI-D-12-006961








doiorg1010800004697319719648324










arctic3995











2889 httpsdoiorg1010022013JD020316





2008JAMC18451




acp-14-2823-2014




JCLI-D-15-06511












334 pp










1011751520-0477(2002)0830255SHBOTA23CO2





172756405781813302




THYOIM20CO2















doiorg1010291998JD200076





1010292002EO000167










1011751520-0442(1998)0113030ACRTAI20CO2



103189172756401781818671







101038srep02039



















273ndash299
























101002grl50190



























































































































































































































ranges






























SYSTEM

















































































































both polar regions
















NCAR)








































































manuscript

APPENDIX










































observation period




































































































































































f SEARCH (2010s)









































REFERENCES





Rep (Part II) 53 pp









2011BAMS32181













doiorg101002wcc337




















Studley Co 40 pp









1010022017GL075841



























doiorg1011751520-0442(2004)0173415PMSOTW20CO2











j1600-0870201100537x








ngeo2016



BAMS-D-16-02151


29ndash31





1010881748-9326102025003



92 (4) 429ndash522





264 httpsdoiorg101080070559002013798582











JCLI-D-15-07751









doiorg101175MWR-D-11-001821





2012GL053385






doiorg101002qj776



JCLI-D-14-004471







JCLI-D-17-02961











1520-0442(1996)0091731OOACAR20CO2




nyp33433000204663

















doiorg1010292018GL077092











1011751520-0469(1945)0020135SMAOTG20CO2



101063PT32449




doiorg101175MWR-D-12-000911



















315207a0



































101002qj2401



101175JAS-33531



2001JD001526



(1960)0170036TDCOTA20CO2



doiorg101002qj49708636802














[154MWIA]20CO2










TGGA20CO2




doiorg101007s00382-012-1512-z



86961989tb07053x











doiorg1011751520-0493(1922)50589aTCA20CO2






BF01054476




BAMS-D-14-002461




1011751520-0477(1992)0731824ISMSAF20CO2










ASAIW20CO2




91015003






doiorg105194tc-8-303-2014





year-2007-2008











101175JCLI-D-13-000141







101002qj49706226601






Printer 28 pp








1520-0469(1975)0320003TEODTC20CO2




SCOAGC23CO2











101029TR027i003p00324




101029TR031i002p00174





















doiorg1010800043167219589925043




















doiorg101175MWR-D-13-003821











jpolar201802001
















101002qj3123



101038328051a0








qj49708134710





101007s00382-011-1196-9





2000JC000705






164 httpsdoiorg101002qj49708235202







s00382-013-1964-9






1011751520-0442(2003)0162078LIVIAM20CO2









1520-0469(1960)0170489TACIS20CO2


Francis 1272 pp









1748-9326aa7def




101175JCLI32531







doiorg1011751520-0469(1960)0170575STCATA20CO2

















1520-0450(1994)0330948AORFAC20CO2









103402tellusav24i110615










TAFZAS20CO2






1011751520-0493(1987)1150444TATF20CO2




1010881748-932693035008








1011751520-0442(2004)0170616CRFOTA20CO2




















1010292009GL039810



2012GL054259

















httpsdoiorg101016S0065-2687(08)60170-3




101175MWR-D-16-03331





doiorg101038321755a0















10 125005 httpsdoiorg1010881748-93261012125005












doiorg101175JCLI-D-12-006961








doiorg1010800004697319719648324










arctic3995











2889 httpsdoiorg1010022013JD020316





2008JAMC18451




acp-14-2823-2014




JCLI-D-15-06511












334 pp










1011751520-0477(2002)0830255SHBOTA23CO2





172756405781813302




THYOIM20CO2















doiorg1010291998JD200076





1010292002EO000167










1011751520-0442(1998)0113030ACRTAI20CO2



103189172756401781818671







101038srep02039



















273ndash299
























101002grl50190



















































































































































































ranges






























SYSTEM

















































































































both polar regions
















NCAR)








































































manuscript

APPENDIX










































observation period




































































































































































f SEARCH (2010s)









































REFERENCES





Rep (Part II) 53 pp









2011BAMS32181













doiorg101002wcc337




















Studley Co 40 pp









1010022017GL075841



























doiorg1011751520-0442(2004)0173415PMSOTW20CO2











j1600-0870201100537x








ngeo2016



BAMS-D-16-02151


29ndash31





1010881748-9326102025003



92 (4) 429ndash522





264 httpsdoiorg101080070559002013798582











JCLI-D-15-07751









doiorg101175MWR-D-11-001821





2012GL053385






doiorg101002qj776



JCLI-D-14-004471







JCLI-D-17-02961











1520-0442(1996)0091731OOACAR20CO2




nyp33433000204663

















doiorg1010292018GL077092











1011751520-0469(1945)0020135SMAOTG20CO2



101063PT32449




doiorg101175MWR-D-12-000911



















315207a0



































101002qj2401



101175JAS-33531



2001JD001526



(1960)0170036TDCOTA20CO2



doiorg101002qj49708636802














[154MWIA]20CO2










TGGA20CO2




doiorg101007s00382-012-1512-z



86961989tb07053x











doiorg1011751520-0493(1922)50589aTCA20CO2






BF01054476




BAMS-D-14-002461




1011751520-0477(1992)0731824ISMSAF20CO2










ASAIW20CO2




91015003






doiorg105194tc-8-303-2014





year-2007-2008











101175JCLI-D-13-000141







101002qj49706226601






Printer 28 pp








1520-0469(1975)0320003TEODTC20CO2




SCOAGC23CO2











101029TR027i003p00324




101029TR031i002p00174





















doiorg1010800043167219589925043




















doiorg101175MWR-D-13-003821











jpolar201802001
















101002qj3123



101038328051a0








qj49708134710





101007s00382-011-1196-9





2000JC000705






164 httpsdoiorg101002qj49708235202







s00382-013-1964-9






1011751520-0442(2003)0162078LIVIAM20CO2









1520-0469(1960)0170489TACIS20CO2


Francis 1272 pp









1748-9326aa7def




101175JCLI32531







doiorg1011751520-0469(1960)0170575STCATA20CO2

















1520-0450(1994)0330948AORFAC20CO2









103402tellusav24i110615










TAFZAS20CO2






1011751520-0493(1987)1150444TATF20CO2




1010881748-932693035008








1011751520-0442(2004)0170616CRFOTA20CO2




















1010292009GL039810



2012GL054259

















httpsdoiorg101016S0065-2687(08)60170-3




101175MWR-D-16-03331





doiorg101038321755a0















10 125005 httpsdoiorg1010881748-93261012125005












doiorg101175JCLI-D-12-006961








doiorg1010800004697319719648324










arctic3995











2889 httpsdoiorg1010022013JD020316





2008JAMC18451




acp-14-2823-2014




JCLI-D-15-06511












334 pp










1011751520-0477(2002)0830255SHBOTA23CO2





172756405781813302




THYOIM20CO2















doiorg1010291998JD200076





1010292002EO000167










1011751520-0442(1998)0113030ACRTAI20CO2



103189172756401781818671







101038srep02039



















273ndash299
























101002grl50190
























































































ranges






























SYSTEM

















































































































both polar regions
















NCAR)








































































manuscript

APPENDIX










































observation period




































































































































































f SEARCH (2010s)









































REFERENCES





Rep (Part II) 53 pp









2011BAMS32181













doiorg101002wcc337




















Studley Co 40 pp









1010022017GL075841



























doiorg1011751520-0442(2004)0173415PMSOTW20CO2











j1600-0870201100537x








ngeo2016



BAMS-D-16-02151


29ndash31





1010881748-9326102025003



92 (4) 429ndash522





264 httpsdoiorg101080070559002013798582











JCLI-D-15-07751









doiorg101175MWR-D-11-001821





2012GL053385






doiorg101002qj776



JCLI-D-14-004471







JCLI-D-17-02961











1520-0442(1996)0091731OOACAR20CO2




nyp33433000204663

















doiorg1010292018GL077092











1011751520-0469(1945)0020135SMAOTG20CO2



101063PT32449




doiorg101175MWR-D-12-000911



















315207a0



































101002qj2401



101175JAS-33531



2001JD001526



(1960)0170036TDCOTA20CO2



doiorg101002qj49708636802














[154MWIA]20CO2










TGGA20CO2




doiorg101007s00382-012-1512-z



86961989tb07053x











doiorg1011751520-0493(1922)50589aTCA20CO2






BF01054476




BAMS-D-14-002461




1011751520-0477(1992)0731824ISMSAF20CO2










ASAIW20CO2




91015003






doiorg105194tc-8-303-2014





year-2007-2008











101175JCLI-D-13-000141







101002qj49706226601






Printer 28 pp








1520-0469(1975)0320003TEODTC20CO2




SCOAGC23CO2











101029TR027i003p00324




101029TR031i002p00174





















doiorg1010800043167219589925043




















doiorg101175MWR-D-13-003821











jpolar201802001
















101002qj3123



101038328051a0








qj49708134710





101007s00382-011-1196-9





2000JC000705






164 httpsdoiorg101002qj49708235202







s00382-013-1964-9






1011751520-0442(2003)0162078LIVIAM20CO2









1520-0469(1960)0170489TACIS20CO2


Francis 1272 pp









1748-9326aa7def




101175JCLI32531







doiorg1011751520-0469(1960)0170575STCATA20CO2

















1520-0450(1994)0330948AORFAC20CO2









103402tellusav24i110615










TAFZAS20CO2






1011751520-0493(1987)1150444TATF20CO2




1010881748-932693035008








1011751520-0442(2004)0170616CRFOTA20CO2




















1010292009GL039810



2012GL054259

















httpsdoiorg101016S0065-2687(08)60170-3




101175MWR-D-16-03331





doiorg101038321755a0















10 125005 httpsdoiorg1010881748-93261012125005












doiorg101175JCLI-D-12-006961








doiorg1010800004697319719648324










arctic3995











2889 httpsdoiorg1010022013JD020316





2008JAMC18451




acp-14-2823-2014




JCLI-D-15-06511












334 pp










1011751520-0477(2002)0830255SHBOTA23CO2





172756405781813302




THYOIM20CO2















doiorg1010291998JD200076





1010292002EO000167










1011751520-0442(1998)0113030ACRTAI20CO2



103189172756401781818671







101038srep02039



















273ndash299
























101002grl50190












SYSTEM

















































































































both polar regions
















NCAR)








































































manuscript

APPENDIX










































observation period




































































































































































f SEARCH (2010s)









































REFERENCES





Rep (Part II) 53 pp









2011BAMS32181













doiorg101002wcc337




















Studley Co 40 pp









1010022017GL075841



























doiorg1011751520-0442(2004)0173415PMSOTW20CO2











j1600-0870201100537x








ngeo2016



BAMS-D-16-02151


29ndash31





1010881748-9326102025003



92 (4) 429ndash522





264 httpsdoiorg101080070559002013798582











JCLI-D-15-07751









doiorg101175MWR-D-11-001821





2012GL053385






doiorg101002qj776



JCLI-D-14-004471







JCLI-D-17-02961











1520-0442(1996)0091731OOACAR20CO2




nyp33433000204663

















doiorg1010292018GL077092











1011751520-0469(1945)0020135SMAOTG20CO2



101063PT32449




doiorg101175MWR-D-12-000911



















315207a0



































101002qj2401



101175JAS-33531



2001JD001526



(1960)0170036TDCOTA20CO2



doiorg101002qj49708636802














[154MWIA]20CO2










TGGA20CO2




doiorg101007s00382-012-1512-z



86961989tb07053x











doiorg1011751520-0493(1922)50589aTCA20CO2






BF01054476




BAMS-D-14-002461




1011751520-0477(1992)0731824ISMSAF20CO2










ASAIW20CO2




91015003






doiorg105194tc-8-303-2014





year-2007-2008











101175JCLI-D-13-000141







101002qj49706226601






Printer 28 pp








1520-0469(1975)0320003TEODTC20CO2




SCOAGC23CO2











101029TR027i003p00324




101029TR031i002p00174





















doiorg1010800043167219589925043




















doiorg101175MWR-D-13-003821











jpolar201802001
















101002qj3123



101038328051a0








qj49708134710





101007s00382-011-1196-9





2000JC000705






164 httpsdoiorg101002qj49708235202







s00382-013-1964-9






1011751520-0442(2003)0162078LIVIAM20CO2









1520-0469(1960)0170489TACIS20CO2


Francis 1272 pp









1748-9326aa7def




101175JCLI32531







doiorg1011751520-0469(1960)0170575STCATA20CO2

















1520-0450(1994)0330948AORFAC20CO2









103402tellusav24i110615










TAFZAS20CO2






1011751520-0493(1987)1150444TATF20CO2




1010881748-932693035008








1011751520-0442(2004)0170616CRFOTA20CO2




















1010292009GL039810



2012GL054259

















httpsdoiorg101016S0065-2687(08)60170-3




101175MWR-D-16-03331





doiorg101038321755a0















10 125005 httpsdoiorg1010881748-93261012125005












doiorg101175JCLI-D-12-006961








doiorg1010800004697319719648324










arctic3995











2889 httpsdoiorg1010022013JD020316





2008JAMC18451




acp-14-2823-2014




JCLI-D-15-06511












334 pp










1011751520-0477(2002)0830255SHBOTA23CO2





172756405781813302




THYOIM20CO2















doiorg1010291998JD200076





1010292002EO000167










1011751520-0442(1998)0113030ACRTAI20CO2



103189172756401781818671







101038srep02039



















273ndash299
























101002grl50190






























































both polar regions
















NCAR)








































































manuscript

APPENDIX










































observation period




































































































































































f SEARCH (2010s)









































REFERENCES





Rep (Part II) 53 pp









2011BAMS32181













doiorg101002wcc337




















Studley Co 40 pp









1010022017GL075841



























doiorg1011751520-0442(2004)0173415PMSOTW20CO2











j1600-0870201100537x








ngeo2016



BAMS-D-16-02151


29ndash31





1010881748-9326102025003



92 (4) 429ndash522





264 httpsdoiorg101080070559002013798582











JCLI-D-15-07751









doiorg101175MWR-D-11-001821





2012GL053385






doiorg101002qj776



JCLI-D-14-004471







JCLI-D-17-02961











1520-0442(1996)0091731OOACAR20CO2




nyp33433000204663

















doiorg1010292018GL077092











1011751520-0469(1945)0020135SMAOTG20CO2



101063PT32449




doiorg101175MWR-D-12-000911



















315207a0



































101002qj2401



101175JAS-33531



2001JD001526



(1960)0170036TDCOTA20CO2



doiorg101002qj49708636802














[154MWIA]20CO2










TGGA20CO2




doiorg101007s00382-012-1512-z



86961989tb07053x











doiorg1011751520-0493(1922)50589aTCA20CO2






BF01054476




BAMS-D-14-002461




1011751520-0477(1992)0731824ISMSAF20CO2










ASAIW20CO2




91015003






doiorg105194tc-8-303-2014





year-2007-2008











101175JCLI-D-13-000141







101002qj49706226601






Printer 28 pp








1520-0469(1975)0320003TEODTC20CO2




SCOAGC23CO2











101029TR027i003p00324




101029TR031i002p00174





















doiorg1010800043167219589925043




















doiorg101175MWR-D-13-003821











jpolar201802001
















101002qj3123



101038328051a0








qj49708134710





101007s00382-011-1196-9





2000JC000705






164 httpsdoiorg101002qj49708235202







s00382-013-1964-9






1011751520-0442(2003)0162078LIVIAM20CO2









1520-0469(1960)0170489TACIS20CO2


Francis 1272 pp









1748-9326aa7def




101175JCLI32531







doiorg1011751520-0469(1960)0170575STCATA20CO2

















1520-0450(1994)0330948AORFAC20CO2









103402tellusav24i110615










TAFZAS20CO2






1011751520-0493(1987)1150444TATF20CO2




1010881748-932693035008








1011751520-0442(2004)0170616CRFOTA20CO2




















1010292009GL039810



2012GL054259

















httpsdoiorg101016S0065-2687(08)60170-3




101175MWR-D-16-03331





doiorg101038321755a0















10 125005 httpsdoiorg1010881748-93261012125005












doiorg101175JCLI-D-12-006961








doiorg1010800004697319719648324










arctic3995











2889 httpsdoiorg1010022013JD020316





2008JAMC18451




acp-14-2823-2014




JCLI-D-15-06511












334 pp










1011751520-0477(2002)0830255SHBOTA23CO2





172756405781813302




THYOIM20CO2















doiorg1010291998JD200076





1010292002EO000167










1011751520-0442(1998)0113030ACRTAI20CO2



103189172756401781818671







101038srep02039



















273ndash299
























101002grl50190
























both polar regions
















NCAR)








































































manuscript

APPENDIX










































observation period




































































































































































f SEARCH (2010s)









































REFERENCES





Rep (Part II) 53 pp









2011BAMS32181













doiorg101002wcc337




















Studley Co 40 pp









1010022017GL075841



























doiorg1011751520-0442(2004)0173415PMSOTW20CO2











j1600-0870201100537x








ngeo2016



BAMS-D-16-02151


29ndash31





1010881748-9326102025003



92 (4) 429ndash522





264 httpsdoiorg101080070559002013798582











JCLI-D-15-07751









doiorg101175MWR-D-11-001821





2012GL053385






doiorg101002qj776



JCLI-D-14-004471







JCLI-D-17-02961











1520-0442(1996)0091731OOACAR20CO2




nyp33433000204663

















doiorg1010292018GL077092











1011751520-0469(1945)0020135SMAOTG20CO2



101063PT32449




doiorg101175MWR-D-12-000911



















315207a0



































101002qj2401



101175JAS-33531



2001JD001526



(1960)0170036TDCOTA20CO2



doiorg101002qj49708636802














[154MWIA]20CO2










TGGA20CO2




doiorg101007s00382-012-1512-z



86961989tb07053x











doiorg1011751520-0493(1922)50589aTCA20CO2






BF01054476




BAMS-D-14-002461




1011751520-0477(1992)0731824ISMSAF20CO2










ASAIW20CO2




91015003






doiorg105194tc-8-303-2014





year-2007-2008











101175JCLI-D-13-000141







101002qj49706226601






Printer 28 pp








1520-0469(1975)0320003TEODTC20CO2




SCOAGC23CO2











101029TR027i003p00324




101029TR031i002p00174





















doiorg1010800043167219589925043




















doiorg101175MWR-D-13-003821











jpolar201802001
















101002qj3123



101038328051a0








qj49708134710





101007s00382-011-1196-9





2000JC000705






164 httpsdoiorg101002qj49708235202







s00382-013-1964-9






1011751520-0442(2003)0162078LIVIAM20CO2









1520-0469(1960)0170489TACIS20CO2


Francis 1272 pp









1748-9326aa7def




101175JCLI32531







doiorg1011751520-0469(1960)0170575STCATA20CO2

















1520-0450(1994)0330948AORFAC20CO2









103402tellusav24i110615










TAFZAS20CO2






1011751520-0493(1987)1150444TATF20CO2




1010881748-932693035008








1011751520-0442(2004)0170616CRFOTA20CO2




















1010292009GL039810



2012GL054259

















httpsdoiorg101016S0065-2687(08)60170-3




101175MWR-D-16-03331





doiorg101038321755a0















10 125005 httpsdoiorg1010881748-93261012125005












doiorg101175JCLI-D-12-006961








doiorg1010800004697319719648324










arctic3995











2889 httpsdoiorg1010022013JD020316





2008JAMC18451




acp-14-2823-2014




JCLI-D-15-06511












334 pp










1011751520-0477(2002)0830255SHBOTA23CO2





172756405781813302




THYOIM20CO2















doiorg1010291998JD200076





1010292002EO000167










1011751520-0442(1998)0113030ACRTAI20CO2



103189172756401781818671







101038srep02039



















273ndash299
























101002grl50190












































































manuscript

APPENDIX










































observation period




































































































































































f SEARCH (2010s)









































REFERENCES





Rep (Part II) 53 pp









2011BAMS32181













doiorg101002wcc337




















Studley Co 40 pp









1010022017GL075841



























doiorg1011751520-0442(2004)0173415PMSOTW20CO2











j1600-0870201100537x








ngeo2016



BAMS-D-16-02151


29ndash31





1010881748-9326102025003



92 (4) 429ndash522





264 httpsdoiorg101080070559002013798582











JCLI-D-15-07751









doiorg101175MWR-D-11-001821





2012GL053385






doiorg101002qj776



JCLI-D-14-004471







JCLI-D-17-02961











1520-0442(1996)0091731OOACAR20CO2




nyp33433000204663

















doiorg1010292018GL077092











1011751520-0469(1945)0020135SMAOTG20CO2



101063PT32449




doiorg101175MWR-D-12-000911



















315207a0



































101002qj2401



101175JAS-33531



2001JD001526



(1960)0170036TDCOTA20CO2



doiorg101002qj49708636802














[154MWIA]20CO2










TGGA20CO2




doiorg101007s00382-012-1512-z



86961989tb07053x











doiorg1011751520-0493(1922)50589aTCA20CO2






BF01054476




BAMS-D-14-002461




1011751520-0477(1992)0731824ISMSAF20CO2










ASAIW20CO2




91015003






doiorg105194tc-8-303-2014





year-2007-2008











101175JCLI-D-13-000141







101002qj49706226601






Printer 28 pp








1520-0469(1975)0320003TEODTC20CO2




SCOAGC23CO2











101029TR027i003p00324




101029TR031i002p00174





















doiorg1010800043167219589925043




















doiorg101175MWR-D-13-003821











jpolar201802001
















101002qj3123



101038328051a0








qj49708134710





101007s00382-011-1196-9





2000JC000705






164 httpsdoiorg101002qj49708235202







s00382-013-1964-9






1011751520-0442(2003)0162078LIVIAM20CO2









1520-0469(1960)0170489TACIS20CO2


Francis 1272 pp









1748-9326aa7def




101175JCLI32531







doiorg1011751520-0469(1960)0170575STCATA20CO2

















1520-0450(1994)0330948AORFAC20CO2









103402tellusav24i110615










TAFZAS20CO2






1011751520-0493(1987)1150444TATF20CO2




1010881748-932693035008








1011751520-0442(2004)0170616CRFOTA20CO2




















1010292009GL039810



2012GL054259

















httpsdoiorg101016S0065-2687(08)60170-3




101175MWR-D-16-03331





doiorg101038321755a0















10 125005 httpsdoiorg1010881748-93261012125005












doiorg101175JCLI-D-12-006961








doiorg1010800004697319719648324










arctic3995











2889 httpsdoiorg1010022013JD020316





2008JAMC18451




acp-14-2823-2014




JCLI-D-15-06511












334 pp










1011751520-0477(2002)0830255SHBOTA23CO2





172756405781813302




THYOIM20CO2















doiorg1010291998JD200076





1010292002EO000167










1011751520-0442(1998)0113030ACRTAI20CO2



103189172756401781818671







101038srep02039



















273ndash299
























101002grl50190

















observation period




































































































































































f SEARCH (2010s)









































REFERENCES





Rep (Part II) 53 pp









2011BAMS32181













doiorg101002wcc337




















Studley Co 40 pp









1010022017GL075841



























doiorg1011751520-0442(2004)0173415PMSOTW20CO2











j1600-0870201100537x








ngeo2016



BAMS-D-16-02151


29ndash31





1010881748-9326102025003



92 (4) 429ndash522





264 httpsdoiorg101080070559002013798582











JCLI-D-15-07751









doiorg101175MWR-D-11-001821





2012GL053385






doiorg101002qj776



JCLI-D-14-004471







JCLI-D-17-02961











1520-0442(1996)0091731OOACAR20CO2




nyp33433000204663

















doiorg1010292018GL077092











1011751520-0469(1945)0020135SMAOTG20CO2



101063PT32449




doiorg101175MWR-D-12-000911



















315207a0



































101002qj2401



101175JAS-33531



2001JD001526



(1960)0170036TDCOTA20CO2



doiorg101002qj49708636802














[154MWIA]20CO2










TGGA20CO2




doiorg101007s00382-012-1512-z



86961989tb07053x











doiorg1011751520-0493(1922)50589aTCA20CO2






BF01054476




BAMS-D-14-002461




1011751520-0477(1992)0731824ISMSAF20CO2










ASAIW20CO2




91015003






doiorg105194tc-8-303-2014





year-2007-2008











101175JCLI-D-13-000141







101002qj49706226601






Printer 28 pp








1520-0469(1975)0320003TEODTC20CO2




SCOAGC23CO2











101029TR027i003p00324




101029TR031i002p00174





















doiorg1010800043167219589925043




















doiorg101175MWR-D-13-003821











jpolar201802001
















101002qj3123



101038328051a0








qj49708134710





101007s00382-011-1196-9





2000JC000705






164 httpsdoiorg101002qj49708235202







s00382-013-1964-9






1011751520-0442(2003)0162078LIVIAM20CO2









1520-0469(1960)0170489TACIS20CO2


Francis 1272 pp









1748-9326aa7def




101175JCLI32531







doiorg1011751520-0469(1960)0170575STCATA20CO2

















1520-0450(1994)0330948AORFAC20CO2









103402tellusav24i110615










TAFZAS20CO2






1011751520-0493(1987)1150444TATF20CO2




1010881748-932693035008








1011751520-0442(2004)0170616CRFOTA20CO2




















1010292009GL039810



2012GL054259

















httpsdoiorg101016S0065-2687(08)60170-3




101175MWR-D-16-03331





doiorg101038321755a0















10 125005 httpsdoiorg1010881748-93261012125005












doiorg101175JCLI-D-12-006961








doiorg1010800004697319719648324










arctic3995











2889 httpsdoiorg1010022013JD020316





2008JAMC18451




acp-14-2823-2014




JCLI-D-15-06511












334 pp










1011751520-0477(2002)0830255SHBOTA23CO2





172756405781813302




THYOIM20CO2















doiorg1010291998JD200076





1010292002EO000167










1011751520-0442(1998)0113030ACRTAI20CO2



103189172756401781818671







101038srep02039



















273ndash299
























101002grl50190













































































f SEARCH (2010s)









































REFERENCES





Rep (Part II) 53 pp









2011BAMS32181













doiorg101002wcc337




















Studley Co 40 pp









1010022017GL075841



























doiorg1011751520-0442(2004)0173415PMSOTW20CO2











j1600-0870201100537x








ngeo2016



BAMS-D-16-02151


29ndash31





1010881748-9326102025003



92 (4) 429ndash522





264 httpsdoiorg101080070559002013798582











JCLI-D-15-07751









doiorg101175MWR-D-11-001821





2012GL053385






doiorg101002qj776



JCLI-D-14-004471







JCLI-D-17-02961











1520-0442(1996)0091731OOACAR20CO2




nyp33433000204663

















doiorg1010292018GL077092











1011751520-0469(1945)0020135SMAOTG20CO2



101063PT32449




doiorg101175MWR-D-12-000911



















315207a0



































101002qj2401



101175JAS-33531



2001JD001526



(1960)0170036TDCOTA20CO2



doiorg101002qj49708636802














[154MWIA]20CO2










TGGA20CO2




doiorg101007s00382-012-1512-z



86961989tb07053x











doiorg1011751520-0493(1922)50589aTCA20CO2






BF01054476




BAMS-D-14-002461




1011751520-0477(1992)0731824ISMSAF20CO2










ASAIW20CO2




91015003






doiorg105194tc-8-303-2014





year-2007-2008











101175JCLI-D-13-000141







101002qj49706226601






Printer 28 pp








1520-0469(1975)0320003TEODTC20CO2




SCOAGC23CO2











101029TR027i003p00324




101029TR031i002p00174





















doiorg1010800043167219589925043




















doiorg101175MWR-D-13-003821











jpolar201802001
















101002qj3123



101038328051a0








qj49708134710





101007s00382-011-1196-9





2000JC000705






164 httpsdoiorg101002qj49708235202







s00382-013-1964-9






1011751520-0442(2003)0162078LIVIAM20CO2









1520-0469(1960)0170489TACIS20CO2


Francis 1272 pp









1748-9326aa7def




101175JCLI32531







doiorg1011751520-0469(1960)0170575STCATA20CO2

















1520-0450(1994)0330948AORFAC20CO2









103402tellusav24i110615










TAFZAS20CO2






1011751520-0493(1987)1150444TATF20CO2




1010881748-932693035008








1011751520-0442(2004)0170616CRFOTA20CO2




















1010292009GL039810



2012GL054259

















httpsdoiorg101016S0065-2687(08)60170-3




101175MWR-D-16-03331





doiorg101038321755a0















10 125005 httpsdoiorg1010881748-93261012125005












doiorg101175JCLI-D-12-006961








doiorg1010800004697319719648324










arctic3995











2889 httpsdoiorg1010022013JD020316





2008JAMC18451




acp-14-2823-2014




JCLI-D-15-06511












334 pp










1011751520-0477(2002)0830255SHBOTA23CO2





172756405781813302




THYOIM20CO2















doiorg1010291998JD200076





1010292002EO000167










1011751520-0442(1998)0113030ACRTAI20CO2



103189172756401781818671







101038srep02039



















273ndash299
























101002grl50190













REFERENCES





Rep (Part II) 53 pp









2011BAMS32181













doiorg101002wcc337




















Studley Co 40 pp









1010022017GL075841



























doiorg1011751520-0442(2004)0173415PMSOTW20CO2











j1600-0870201100537x








ngeo2016



BAMS-D-16-02151


29ndash31





1010881748-9326102025003



92 (4) 429ndash522





264 httpsdoiorg101080070559002013798582











JCLI-D-15-07751









doiorg101175MWR-D-11-001821





2012GL053385






doiorg101002qj776



JCLI-D-14-004471







JCLI-D-17-02961











1520-0442(1996)0091731OOACAR20CO2




nyp33433000204663

















doiorg1010292018GL077092











1011751520-0469(1945)0020135SMAOTG20CO2



101063PT32449




doiorg101175MWR-D-12-000911



















315207a0



































101002qj2401



101175JAS-33531



2001JD001526



(1960)0170036TDCOTA20CO2



doiorg101002qj49708636802














[154MWIA]20CO2










TGGA20CO2




doiorg101007s00382-012-1512-z



86961989tb07053x











doiorg1011751520-0493(1922)50589aTCA20CO2






BF01054476




BAMS-D-14-002461




1011751520-0477(1992)0731824ISMSAF20CO2










ASAIW20CO2




91015003






doiorg105194tc-8-303-2014





year-2007-2008











101175JCLI-D-13-000141







101002qj49706226601






Printer 28 pp








1520-0469(1975)0320003TEODTC20CO2




SCOAGC23CO2











101029TR027i003p00324




101029TR031i002p00174





















doiorg1010800043167219589925043




















doiorg101175MWR-D-13-003821











jpolar201802001
















101002qj3123



101038328051a0








qj49708134710





101007s00382-011-1196-9





2000JC000705






164 httpsdoiorg101002qj49708235202







s00382-013-1964-9






1011751520-0442(2003)0162078LIVIAM20CO2









1520-0469(1960)0170489TACIS20CO2


Francis 1272 pp









1748-9326aa7def




101175JCLI32531







doiorg1011751520-0469(1960)0170575STCATA20CO2

















1520-0450(1994)0330948AORFAC20CO2









103402tellusav24i110615










TAFZAS20CO2






1011751520-0493(1987)1150444TATF20CO2




1010881748-932693035008








1011751520-0442(2004)0170616CRFOTA20CO2




















1010292009GL039810



2012GL054259

















httpsdoiorg101016S0065-2687(08)60170-3




101175MWR-D-16-03331





doiorg101038321755a0















10 125005 httpsdoiorg1010881748-93261012125005












doiorg101175JCLI-D-12-006961








doiorg1010800004697319719648324










arctic3995











2889 httpsdoiorg1010022013JD020316





2008JAMC18451




acp-14-2823-2014




JCLI-D-15-06511












334 pp










1011751520-0477(2002)0830255SHBOTA23CO2





172756405781813302




THYOIM20CO2















doiorg1010291998JD200076





1010292002EO000167










1011751520-0442(1998)0113030ACRTAI20CO2



103189172756401781818671







101038srep02039



















273ndash299
























101002grl50190







92 (4) 429ndash522





264 httpsdoiorg101080070559002013798582











JCLI-D-15-07751









doiorg101175MWR-D-11-001821





2012GL053385






doiorg101002qj776



JCLI-D-14-004471







JCLI-D-17-02961











1520-0442(1996)0091731OOACAR20CO2




nyp33433000204663

















doiorg1010292018GL077092











1011751520-0469(1945)0020135SMAOTG20CO2



101063PT32449




doiorg101175MWR-D-12-000911



















315207a0



































101002qj2401



101175JAS-33531



2001JD001526



(1960)0170036TDCOTA20CO2



doiorg101002qj49708636802














[154MWIA]20CO2










TGGA20CO2




doiorg101007s00382-012-1512-z



86961989tb07053x











doiorg1011751520-0493(1922)50589aTCA20CO2






BF01054476




BAMS-D-14-002461




1011751520-0477(1992)0731824ISMSAF20CO2










ASAIW20CO2




91015003






doiorg105194tc-8-303-2014





year-2007-2008











101175JCLI-D-13-000141







101002qj49706226601






Printer 28 pp








1520-0469(1975)0320003TEODTC20CO2




SCOAGC23CO2











101029TR027i003p00324




101029TR031i002p00174





















doiorg1010800043167219589925043




















doiorg101175MWR-D-13-003821











jpolar201802001
















101002qj3123



101038328051a0








qj49708134710





101007s00382-011-1196-9





2000JC000705






164 httpsdoiorg101002qj49708235202







s00382-013-1964-9






1011751520-0442(2003)0162078LIVIAM20CO2









1520-0469(1960)0170489TACIS20CO2


Francis 1272 pp









1748-9326aa7def




101175JCLI32531







doiorg1011751520-0469(1960)0170575STCATA20CO2

















1520-0450(1994)0330948AORFAC20CO2









103402tellusav24i110615










TAFZAS20CO2






1011751520-0493(1987)1150444TATF20CO2




1010881748-932693035008








1011751520-0442(2004)0170616CRFOTA20CO2




















1010292009GL039810



2012GL054259

















httpsdoiorg101016S0065-2687(08)60170-3




101175MWR-D-16-03331





doiorg101038321755a0















10 125005 httpsdoiorg1010881748-93261012125005












doiorg101175JCLI-D-12-006961








doiorg1010800004697319719648324










arctic3995











2889 httpsdoiorg1010022013JD020316





2008JAMC18451




acp-14-2823-2014




JCLI-D-15-06511












334 pp










1011751520-0477(2002)0830255SHBOTA23CO2





172756405781813302




THYOIM20CO2















doiorg1010291998JD200076





1010292002EO000167










1011751520-0442(1998)0113030ACRTAI20CO2



103189172756401781818671







101038srep02039



















273ndash299
























101002grl50190






























101002qj2401



101175JAS-33531



2001JD001526



(1960)0170036TDCOTA20CO2



doiorg101002qj49708636802














[154MWIA]20CO2










TGGA20CO2




doiorg101007s00382-012-1512-z



86961989tb07053x











doiorg1011751520-0493(1922)50589aTCA20CO2






BF01054476




BAMS-D-14-002461




1011751520-0477(1992)0731824ISMSAF20CO2










ASAIW20CO2




91015003






doiorg105194tc-8-303-2014





year-2007-2008











101175JCLI-D-13-000141







101002qj49706226601






Printer 28 pp








1520-0469(1975)0320003TEODTC20CO2




SCOAGC23CO2











101029TR027i003p00324




101029TR031i002p00174





















doiorg1010800043167219589925043




















doiorg101175MWR-D-13-003821











jpolar201802001
















101002qj3123



101038328051a0








qj49708134710





101007s00382-011-1196-9





2000JC000705






164 httpsdoiorg101002qj49708235202







s00382-013-1964-9






1011751520-0442(2003)0162078LIVIAM20CO2









1520-0469(1960)0170489TACIS20CO2


Francis 1272 pp









1748-9326aa7def




101175JCLI32531







doiorg1011751520-0469(1960)0170575STCATA20CO2

















1520-0450(1994)0330948AORFAC20CO2









103402tellusav24i110615










TAFZAS20CO2






1011751520-0493(1987)1150444TATF20CO2




1010881748-932693035008








1011751520-0442(2004)0170616CRFOTA20CO2




















1010292009GL039810



2012GL054259

















httpsdoiorg101016S0065-2687(08)60170-3




101175MWR-D-16-03331





doiorg101038321755a0















10 125005 httpsdoiorg1010881748-93261012125005












doiorg101175JCLI-D-12-006961








doiorg1010800004697319719648324










arctic3995











2889 httpsdoiorg1010022013JD020316





2008JAMC18451




acp-14-2823-2014




JCLI-D-15-06511












334 pp










1011751520-0477(2002)0830255SHBOTA23CO2





172756405781813302




THYOIM20CO2















doiorg1010291998JD200076





1010292002EO000167










1011751520-0442(1998)0113030ACRTAI20CO2



103189172756401781818671







101038srep02039



















273ndash299
























101002grl50190









101175JCLI-D-13-000141







101002qj49706226601






Printer 28 pp








1520-0469(1975)0320003TEODTC20CO2




SCOAGC23CO2











101029TR027i003p00324




101029TR031i002p00174





















doiorg1010800043167219589925043




















doiorg101175MWR-D-13-003821











jpolar201802001
















101002qj3123



101038328051a0








qj49708134710





101007s00382-011-1196-9





2000JC000705






164 httpsdoiorg101002qj49708235202







s00382-013-1964-9






1011751520-0442(2003)0162078LIVIAM20CO2









1520-0469(1960)0170489TACIS20CO2


Francis 1272 pp









1748-9326aa7def




101175JCLI32531







doiorg1011751520-0469(1960)0170575STCATA20CO2

















1520-0450(1994)0330948AORFAC20CO2









103402tellusav24i110615










TAFZAS20CO2






1011751520-0493(1987)1150444TATF20CO2




1010881748-932693035008








1011751520-0442(2004)0170616CRFOTA20CO2




















1010292009GL039810



2012GL054259

















httpsdoiorg101016S0065-2687(08)60170-3




101175MWR-D-16-03331





doiorg101038321755a0















10 125005 httpsdoiorg1010881748-93261012125005












doiorg101175JCLI-D-12-006961








doiorg1010800004697319719648324










arctic3995











2889 httpsdoiorg1010022013JD020316





2008JAMC18451




acp-14-2823-2014




JCLI-D-15-06511












334 pp










1011751520-0477(2002)0830255SHBOTA23CO2





172756405781813302




THYOIM20CO2















doiorg1010291998JD200076





1010292002EO000167










1011751520-0442(1998)0113030ACRTAI20CO2



103189172756401781818671







101038srep02039



















273ndash299
























101002grl50190







101007s00382-011-1196-9





2000JC000705






164 httpsdoiorg101002qj49708235202







s00382-013-1964-9






1011751520-0442(2003)0162078LIVIAM20CO2









1520-0469(1960)0170489TACIS20CO2


Francis 1272 pp









1748-9326aa7def




101175JCLI32531







doiorg1011751520-0469(1960)0170575STCATA20CO2

















1520-0450(1994)0330948AORFAC20CO2









103402tellusav24i110615










TAFZAS20CO2






1011751520-0493(1987)1150444TATF20CO2




1010881748-932693035008








1011751520-0442(2004)0170616CRFOTA20CO2




















1010292009GL039810



2012GL054259

















httpsdoiorg101016S0065-2687(08)60170-3




101175MWR-D-16-03331





doiorg101038321755a0















10 125005 httpsdoiorg1010881748-93261012125005












doiorg101175JCLI-D-12-006961








doiorg1010800004697319719648324










arctic3995











2889 httpsdoiorg1010022013JD020316





2008JAMC18451




acp-14-2823-2014




JCLI-D-15-06511












334 pp










1011751520-0477(2002)0830255SHBOTA23CO2





172756405781813302




THYOIM20CO2















doiorg1010291998JD200076





1010292002EO000167










1011751520-0442(1998)0113030ACRTAI20CO2



103189172756401781818671







101038srep02039



















273ndash299
























101002grl50190











1010292009GL039810



2012GL054259

















httpsdoiorg101016S0065-2687(08)60170-3




101175MWR-D-16-03331





doiorg101038321755a0















10 125005 httpsdoiorg1010881748-93261012125005












doiorg101175JCLI-D-12-006961








doiorg1010800004697319719648324










arctic3995











2889 httpsdoiorg1010022013JD020316





2008JAMC18451




acp-14-2823-2014




JCLI-D-15-06511












334 pp










1011751520-0477(2002)0830255SHBOTA23CO2





172756405781813302




THYOIM20CO2















doiorg1010291998JD200076





1010292002EO000167










1011751520-0442(1998)0113030ACRTAI20CO2



103189172756401781818671







101038srep02039



















273ndash299
























101002grl50190








1011751520-0477(2002)0830255SHBOTA23CO2





172756405781813302




THYOIM20CO2















doiorg1010291998JD200076





1010292002EO000167










1011751520-0442(1998)0113030ACRTAI20CO2



103189172756401781818671







101038srep02039



















273ndash299
























101002grl50190




