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Arctic sea ice extent and thickness is declining
The average thickness of the Arctic’s sea ice declined by 30% from 2003 to 2008.
The last four years have seen the lowest four minimum extents ever recorded for Arctic sea ice.
Feb-Mar 2003
Feb-Mar 2008
FARRELL ET AL., JOURNAL OF GEOPHYSICAL RESEARCH, 2009
NASA’s researchers and satellite and aircraft observation tools are global leaders of this work. This work is critical to understanding polar feedbacks into global climate, as well as meeting US planning needs in the Arctic; from understanding environmental change to security and economic decisions
Shifts in sea ice persistence and Chl-a concentration from 2003-2009 Courtesy Frey&Grebmeier
Based on SSM/I Sea Ice Concentrations and the GlobColour satellite time series,
Take home points:
• Satellites map changes in base of food chain
• Major contribution to Distributed Biological Observatory
• Critical to understanding future resources and livelihoods for the Alaskan economy, as well
as feedbacks for global carbon budget
NASA’s ICESCAPE cruise to improve understanding of Arctic
ocean ecosystems made the discovery of phytoplankton concentration amongst the highest ever observed anywhere on earth. Even more astounding it was under thick sea ice with limited light penetration.
Unique approaches to understanding the elusive Arctic Mapping ocean currents from satellite:
Changing Arctic Ocean Freshwater Pathways
Morison, J., R. Kwok, C. Peralta-Ferriz, M. Alkire, I. Rigor, R. Andersen, and M. Steele. Nature 481, 66-70 (2012) doi:10.1038/nature10705
• Sea surface height from ICESat and ocean bottom pressure trends from GRACE show Canada Basin freshwater content increase balanced by decrease in the Eurasian Basin (2005-2008).
• Chemistry observations show the Canada Basin freshwater increase due to increased presence of Eurasian runoff.
• Satellite observations show changes due to counterclockwise shift in the ocean pathway of Eurasian runoff forced by strengthening of the west-to-east Arctic Oscillation (AO).
• This high-AO process likely characterizes the dramatic Arctic Ocean changes since the early 1990s. Climate models must capture the Arctic expression of the AO accurately if they are to project the fate of Arctic freshwater and its effect on climate.
Right-Top: ICESat measured sea surface height trends
(contours) which determine near surface ocean pressure gradients
that drive surface currents (arrows).
Bottom: ocean bottom pressure trend minus ICESat sea surface
height trend yields countours of steric pressure trends and
freshwater content trend.
1
2
3
4
5
6
7
8
+3 Gt/yr +15
Gt/yr
-41 Gt/yr
-69 Gt/yr
-9
Gt/y
r
-3
Gt/yr
-14
Gt/yr
-33
Gt/yr
-151 Gt/yr
total
2003 to 2007
ELA 2000 m
Ice sheet and glacier mass change NASA scientists use a range of satellites, aircraft missions, and other approaches with an overall goal of improving estimates of current and future sea level rise
Images courtesy
Larsen, Vaughan,
Zwally, Joughin
and Luthcke
Operation IceBridge
IceBridge is also making other key measurements to improve predictive models for ice-sheet evolution.
Bridging the gap between the ICESat and ICESat-2 missions, NASA is deploying aircraft to monitor the Greenland and Antarctic ice sheets, as well as sea ice in both regions.
7
Comprehensive Imaging of Ice Sheets and Ice
Shelves from Top to Bottom
with IceBridge Instrument Suite
Pine Island Glacier, Antarctica, 2009
Images illustrate the deep trough upstream of the floating Pine Island Glacier tongue. Also evident are several tributary glaciers that traverse mountainous terrain on the eastern flank of the glacier. Results show the generally excellent correspondence between the ASAID grounding line and subsurface topography, though in some places OIB data can be used to refine grounding line placement. Qualitatively, surface velocity directions are consistent with subglacial topography suggesting that flow divergence with depth may be small.
Image from Jezek and Dhanasekaran (Dhanasekaran M.S Thesis, 2011, The Ohio State University)
bathymetry from gravity inversion (Studinger)
bottom of ice sheet from radar (CReSIS)
ice surface from ATM and Radarsat (ATM and Jezek)
Ice Cloud and land Elevation Satellite-2 (ICESat-2)
Ice sheet mass balance from elevation change
Sea ice thickness from freeboard
Large-scale biomass from vegetation height
3 sets of 2 beams • density of coverage • simultaneous
measurement slope and elevation
Micropulse lidar • Low energy • High rep-rate • 70 cm along-track sampling
Waleed Abdalati, ESOC/CIRES, Univ. of Colorado, IPCC Sea Level Meeting, Kuala Lumpur, Malaysia, June 21-24, 2010
11
12
Remote sensing data can offer regional context, help address uncertainties, and inform and assess models
Change in Arctic & Boreal Region (ABR) unfolding faster than anywhere else on Earth
NASA’s Carbon Cycle & Ecosystems Program is planning
Arctic-Boreal Vulnerability Experiment (ABoVE), a major field, aircraft, and space-based remote sensing campaign
NSIDC: An overview 14
National Snow and Ice Data Center: A NASA Distributed Active Archive Center (DAAC) for the cryosphere
• Hosts >100 Tb of data, and distributes more than double that each year
• Includes Earth System Data Records: integrated, multi-year to decadal datasets that improve usability for other disciplines, e.g. freeze-thaw, temp, sea ice motion
• AMSR-E (Aqua)
• AMSR (ADEOS II)
• SMMR (Nimbus 7)
• SSM/I, SSMIS (DMSP
series)
VIS/IR Moderate
Resolution
• MODIS (Terra/Aqua)
snow and ice products
• AVHRR polar data
(NOAA series)
Satellite & Airborne
Altimetry
• ICESat I/GLAS altimetry
and atmospheric lidar data
• Digital Elevation Models
(DEMs)
• IceBridge
Passive Microwave
AMSR-E 12.5 km Sea Ice Concentration MODIS Monthly Global Snow Cover IceBridge ATM Qfit Data on Landsat Image
Earth System Data Records: integrating and improving usability for other disciplines
NASA has made major awards to synthesize satellite records critical to polar work, including:
Courtesy U. Montana/JPL
• Greenland ice sheet velocities (InSAR) • Antarctic ice sheet velocities (InSAR) • Arctic sea ice kinematics
• Global snow cover (30-yr record) • Daily freeze-thaw maps (below)
Products at NSIDC
MEaSUREs
ESDR (Earth Science Data Record) of Small-Scale Kinematics of the Arctic and Southern Oceans: A new data set based on Envisat
Science uses of ice motion products • Assess linear kinematic features (fracture
patterns) in new models of anisotropic sea mechanics
• Subdaily ice motion for understanding impact of small-scale and short-timescale ice deformation on ice production
• Study of oceanic heat flux due at shear lines in the ice cover (i.e., doming of the pycnocline)
• Ice area export at the Nares Strait and Fram Strait
• Validation of lower resolution ice drift in lower resolution sensors
• Users: • (US) Naval Postgraduate School, U New
Mexico U Washingto, JPL • (Europe) Nansen Remote Sensing Center, U of
Reading, U of Grenoble, Alfred Wegener Institute, Norwegian Polar Insitute, ESA CCI ECV ice drift, U Hamburg
• (Australia) U of Tasmania
Ron Kwok, Jet Propulsion Laboratory Composite deformation fields of the Weddell Sea ice cover from 1-day motion Envisat
Div
erge
nce
Vor
tici
ty
Shea
r
MEaSUREs
ESDR (Earth Science Data Record) of Small-Scale Kinematics of the Arctic and Southern Oceans: A new data set based on Envisat
Description and Objectives • Process the Envisat data stream (2007-2012) to
construct ESDRs of small-scale ice motion of the Arctic and Southern Oceans;
• Develop products that take advantage of the temporal (subdaily to 1-day) and spatial sampling scheme of the Envisat mission;
• Produce mosaics of the Envisat images of the Arctic Ocean;
• Create a multi-year time series of Fram Strait and Nares Strait sea ice export;
• Address the use of Sentinel-1 data sets for producing ESDR of the Arctic and Antarctic ice cover.
• Note: Sentinel-1 data are needed to continue record of changes in small-scale deformation
Ron Kwok, Jet Propulsion Laboratory Composite deformation fields of the Arctic Ocean ice cover
from 1-day motion Envisat
Div
erge
nce
Vor
tici
ty
Shea
r
X-m
otio
n Y
-mot
ion
Tot
al M
otio
n
TSX provides more limited coverage but captures most fast-
moving outlets at high-resolution and more frequent
sampling
Both targeted high res (TSX-like) coverage and lower res
(RADARSAT-like) coverage are crucial for understanding
flow variability in Greenland.
Velocity mapping of the Great Ice Sheets: Antarctica NASA MEaSUREs-1 (2006-2012). PI: E. Rignot, Proj. Scientists J. Mouginot and B. Scheuchl
Objective Develop and distribute a new set of Earth System Data Records (ESDR) of ice velocity in Antarctica. Goal Assemble and distribute the first true continent-wide ice velocity map of Antarctica. This project would not have been possible without the support from STG
Approach • Build on existing extensive team
expertise and scale up for continent-wide processing.
• Work with space agencies (i.e. STG) to gain international support and access to IPY large scale SAR acquisition campaigns.
Achievements Multiple continent products completed:
• First ever continent-wide velocity map • Interferometric grounding line map • Time series of velocity in key areas
Key publications in high profile journals.
Significant international media attention.
Widespread use of the ESDRs in the science community.
Ice velocity and grounding line products available at NSIDC http://nsidc.org/data/measures/data_summaries.html
Ice Velocity Mapping of the Antarctic Ice Sheet NASA MEaSUREs-2 (2013-2018). PI: Eric Rignot, Proj. Scientists J. Mouginot and B. Scheuchl
Objective Produce and distribute Earth System Data Records (ESDR) of ice velocity in Antarctica.
Goals
Time series of ice velocity from 1996, 2000, 2006-2013, to present. PSTG support is critical for project success
Approach • Build time series of selected regions and
ice sheet wide mapping on select years. • Historic data sets (RAMP 2000, ERS-1
1996). • Work with space agencies to plan and
implement future data acquisitions. • Advise NISAR project team on ice sheet
requirements (separate contract).
Achievements: Amundsen Sea.
Rignot, E., J. Mouginot, M. Morlighem, H. Seroussi, and B. Scheuchl (2014), Widespread, rapid grounding line retreat of Pine Island, Thwaites, Smith, and Kohler glaciers, West Antarctica, from 1992 to 2011, Geophys. Res. Lett., 41, 3502–3509, doi:10.1002/2014GL060140. Mouginot, J., E. Rignot, and B. Scheuchl (2014), Sustained increase in ice discharge from the Amundsen Sea Embayment, West Antarctica, from 1973 to 2013, Geophys. Res. Lett., 41, 1576–1584, doi:10.1002/2013GL059069.
Widespread international media coverage of the findings. US: reached two out of three national TV news broadcasts and the top tier newspapers in the country. Time series of Amundsen sea since 1975 released at NSIDC.
1996
100 km
A1
A2
B1
B2
C1
C2
D1
D2E1
E2F1
F2G1
G2
(a)
2008 - 1996
100 km
(b)
Pine Island Gl.
Thwaites Gl.
Haynes Gl.
Pope Gl.
Smith Gl.
Kohler Gl.
Eastern IS
Thwaites Ice Tongue
Crosson
Dotson
Ice Velocity (km/yr)
<0.0015 0.01 0.1 1 >3 <-1.5 -0.1 -0.01 >1.50.10.01
Vel. difference (km/yr)
Evolution of ice velocity in the Amundsen Sea Embayment area
Ice Velocity Mapping of the Antarctic Ice Sheet NASA MEaSUREs-2 (2013-2018). PI: Eric Rignot, Proj. Scientists J. Mouginot and B. Scheuchl
What we have, thanks to PSTG: • Access to RAMP-1, ERS-1 archive from 1995-
1996, all ALOS PALSAR 2006-2010. • Access to Sentinel-1 starting January 1, 2015. • Antarctic campaigns of RADARSAT-2 in 2013. • Limited access to TanDEM-X and TerraSAR-X. • Access to Landsat 8 for coastal mapping (not
planned initially).
What we need, with the help from PSTG: • More systematic acquisitions from Sentinel1a/1b
over Antarctica using a fixed set of tracks in order to build time series at the continental scale.
• Access to COSMO Skymed for short time repeat and grounding line mapping in Amundsen Sea and other key sectors.
• Access to ALOS-2 PALSAR planned data acquisitions (acquisitions planned but data access is limited).
• Larger access to TerraSAR-X archive.
1996
100 km
A1
A2
B1
B2
C1
C2
D1
D2E1
E2F1
F2G1
G2
(a)
2008 - 1996
100 km
(b)
Pine Island Gl.
Thwaites Gl.
Haynes Gl.
Pope Gl.
Smith Gl.
Kohler Gl.
Eastern IS
Thwaites Ice Tongue
Crosson
Dotson
Ice Velocity (km/yr)
<0.0015 0.01 0.1 1 >3 <-1.5 -0.1 -0.01 >1.50.10.01
Vel. difference (km/yr)
Evolution of ice velocity in the Amundsen Sea Embayment area
COSMO Skymed grounding line of Petermann Gl. In 2013.
This site allows DBO researchers quick access to key remote sensing datasets for marine observations:
Wind speed
Ocean color (Chlorophyll)
Sea surface temperature
Sea ice concentration
Cloud cover
Surface pressure
NASA’s Distributed Biological Observatory (DBO) site Bridging the gap to help IARPC agencies and scientists lacking remote sensing experience through websites, viewers, and integrated datasets to help them put Arctic change in context.
• Temperature
• Freeze thaw
• Vegetation change (NDVI)
• Water vapor
• Snow cover
• Sea ice cover
• Others in development
Satellite records of the critical Arctic variables—some spanning three decades. Allows users to see change across entire Arctic down to pixel level of the data.
Satellite Observations of Arctic Change