Chapter 8: Climate and Climate Change. Climate Classification Purpose of Classifying Climates...
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Chapter 8: Climate and Climate Change. Climate Classification Purpose of Classifying Climates –Understand climate distribution –Compare climates of different
Climate Classification Purpose of Classifying Climates
Understand climate distribution Compare climates of different
places Temperature & precipitation typically used Vegetation
Earliest scheme = ancient Greeks 2200 years ago Classified 3
climate regions based on latitude Torrid, Temperate, Frigid Figure
8-1
Slide 3
Climate Classification Kppen climate classification system
Based on annual & monthly average temperature &
precipitation A, B, C, D, E, H* 4 of 5 major groups classified by
temperature 5 th group classified by precipitation Subdivided
further based on temperature & precipitation relationships
Figure 8-2
Slide 4
Climate Classification Kppen 3 letter code system 1 st = group
2 nd = precipitation 3 rd = temperature
Slide 5
World Distribution of Major Climate Types Figure 8-11 Weather
records: How do we explain their locations?
Slide 6
Three Questions Where are various climate types located? What
are the characteristics of each climate? What are the main controls
of each climate? Climograph Graphic representation of monthly
temperature & precipitation World Distribution of Major Climate
Types Figure 8-4
Slide 7
World Distribution of Major Climate Types Tropical Humid
Climates (A) Tropics (0-25 N/S) Winterless climates; little
temperature change High temperatures & prevalent moisture
Precipitation influenced by ITCZ 3 subtypes Divided based on
monthly rainfall Figure 8-5
Slide 8
World Distribution of Major Climate Types Tropical wet climate
(Af) Equatorial (0-10 N/S) Monotonous Daily temperature range >
annual range High humidity High precipitation Multiple rains daily
Afternoon convective storms Evenly distributed rain during year
Influenced by ITCZ High solar angle year round Figures 8-6a &
b
Slide 9
World Distribution of Major Climate Types Tropical savannah
climate (Aw) N/S of Af climates Most extensive A climate Seasonal
wet/dry alteration due to ITCZ position Lowest tropical rainfall
amounts Dominant Controls Summer: ITCZ Winter: cT or cP air masses
Figures 8-8a & b
Slide 10
World Distribution of Major Climate Types Tropical monsoonal
climate (Am) Prominent monsoon wind patterns Coastal areas
Extensive rainfall during summer Cherrapunji, India = 425 in Cloud
cover reduces summer temperatures Dominant Controls ITCZ movement
Jet stream fluctuation Continental pressure changes Figures 8-10a
& b
Slide 11
World Distribution of Major Climate Types Dry climates (B)
Cover about 30% of land area worldwide Dry conditions all year PE
> P Lack of uplift or lack of moisture 2 main types
(precipitation) Desert Steppe 2 subtypes (temperature) Subtropical
Midlatitude Figure 8-12
Slide 12
World Distribution of Major Climate Types Subtropical desert
climate (BWh) Near STHs (30 N/S) Precipitation is scarce,
unreliable, intense & short- lived Hot temperatures Large daily
temperature range Dominant Controls Subsidence from (STHs) Cold
ocean currents Figures 8-14a & b
Slide 13
World Distribution of Major Climate Types Subtropical steppe
climate (BSh) Fringe BWh climates Separate deserts from humid
climates Less extremes Cooler & more rainfall (semi-arid)
Seasonal rainfall concentration Dominant Controls Similar to BWh
Figure 8-17
Slide 14
World Distribution of Major Climate Types Midlatitude desert
climate (BWk) Meager & erratic precipitation Mostly in summer
Cooler temperatures Hot summers & cold winters Greater annual
& daily temperature range Dominant Controls Rain shadow effects
Distance from moisture sources Figures 8-18a & b
Slide 15
World Distribution of Major Climate Types Midlatitude steppe
climate (BSk) Rringe BWk climates Transition between desert &
humid climates More precipitation than mid- latitude deserts
(semi-arid) Less temperature extremes than mid- latitude deserts
Dominant Controls Similar to BWk Figure 8-19
Slide 16
World Distribution of Major Climate Types Mild Midlatitude
Climates (C) Transition between warmer tropical climates &
colder severe midlatitude climates Equator-ward side of
mid-latitudes Long, hot summers & short, mild winters Highly
variable precipitation 3 primary groups Figure 8-20
Slide 17
World Distribution of Major Climate Types Mediterranean Climate
(Csa, Csb) West sides of continents Modest precipitation in winter,
summer is virtually rainless Mild, wet winters & hot, dry
summers Clear skies especially in summer Dominant Controls Summer:
STH Winter: westerlies & cyclones Figures 8-21a & b
Slide 18
World Distribution of Major Climate Types Humid Subtropical
Climate (Cfa, Cwa) East sides of continents Warm to hot summers;
high humidity Hot & humid Precipitation reaches summer maximum,
less in winter Winter temperatures are mild to cold Figures 8-24a
& b
Slide 19
World Distribution of Major Climate Types Marine West Coast
Climate (Cfb, Cfc) West sides of continents Often cloudy with
precipitation Wettest of midlatitudes Max precipitation in winter
Temperate climate Very mild winters for latitude Dominant Controls
Westerly winds & oceanic influence year-round Figures 8-26a
& b
Slide 20
World Distribution of Major Climate Types Severe Midlatitude
Climates (D) Only in Northern Hemisphere Continentalityremoteness
from oceans Large annual temperature range Precipitation varies;
diminishes inland & poleward 4 recognizable seasons Long, cold
winter & shorter summer Subdivided into 2 types Figure
8-27
Slide 21
World Distribution of Major Climate Types Humid Continental
Climate (Dfa, Dfb, Dwa, Dwb) East sides of continents in N.
Hemisphere Dominated by westerlies & frequent weather changes
Warm/hot summers, cold winters Large annual temperature range
Generally low precipitation Higher near coasts Winter precipitation
= cyclones; summer precipitation = convection Our climate in NE
Figures 8-28a & b
Slide 22
World Distribution of Major Climate Types Subarctic Climate
(Dfc, Dfd, Dwc, Dwd) Winters are long, dark, bitterly cold Summers
are short Spring & fall are very short Coldest temperatures;
little precipitation Largest annual temperature ranges (-90 F to 98
F in Verhoyansk, Siberia) Dominant Controls Continentality
Alternate between: Westerlies/storms Anticylcones Figures 8-31a
& b
Slide 23
World Distribution of Major Climate Types Polar Climates (Group
E) Receive little insolation Coldest summers No average temperature
above 50 F Large annual temperature range Small daily temperature
range Extremely dry, but classified as non-arid Low evaporation 2
primary groups Figure 8-27
Slide 24
World Distribution of Major Climate Types Tundra Climate (ET)
Long, dark winters Winters not as severely cold as subarctic
climate Brief, cool summers Little precipitation Dominant Controls
Latitude Distance from heat/moisture sources Extreme contrasts in
sunlight/darkness Polar anticyclones (A & cP air masses)
Figures 8-33a & b
Slide 25
World Distribution of Major Climate Types Ice Cap Climate (EF)
Greenland & Antarctica Permanent ice & snow cover High
latitude with high altitude Very limited precipitation Polar
deserts Dominant Controls Similar to ET Figures 8-34a & b
Slide 26
World Distribution of Major Climate Types Highland Climate (H)
Infinite variations from place to place Vertical climate zonation
Altitude vs. Latitude Altitude = more significant in highlands
-6.5C /1000m Exposure: windward or leeward Figure 8-36
Slide 27
Global Patterns Idealized Understand climate locations &
relationships Presumed arrangement of climate types on hypothetical
continent Example: Africa Only continent with equal land N/S of
equator Figures 8-39 & 40
Slide 28
Global Climate Change Changes in climate on long time scales
Episodic events vs. long-term global climate change Numerous time
scales 70 million years: global cooling trend 150,000 years:
temperature fluctuated 10,000 years: sharp warmup 150 years:
warming trend relative to last 1000 years Figure 8-41
Slide 29
Global Climate Change Paleoclimatology Proxy measures of
climate Dendrochronology Study of past climate via tree ring
analysis Oxygen isotope analysis/Ice cores Lighter vs. heavier
isotopes ( 18 O : 16 O) Ratio of 18 O/ 16 O = thermometer
Atmospheric composition measurements Coral reefs Ratio of 18 O/ 16
O & reef height Pollen data Radiocarbon dating Figure 8-42
Slide 30
Global Climate Change Causes of Long-Term Climate Change
Atmospheric aerosols Block insolation & lower temperature Due
to volcanic eruptions or asteroid impacts Anthropogenic impacts
Solar output fluctuations Sunspot activity vs. solar output Roles
of the oceans Absorb large amounts of carbon Methane hydrates Heat
transfer from low latitudes to high latitudes Figures 8-43 &
45
Slide 31
Global Climate Change Climate change causes (cont.) Greenhouse
gas concentrations Greenhouse gas concentrations related to
temperature Evidence of CO 2 increase being anthropogenic Feedback
mechanisms Positive feedback mechanisms Negative feedback
mechanisms Variations in Earth-Sun relations Milankovitch cycles
Shape of Earths orbit (eccentricty) Inclination of Earths axis
(obliquity) Position of Earths axis (precession) Figure 8-44
Slide 32
Global Climate Change Evidence of global warming 11 of 12
warmest years on record occurred between 19952006 Global
temperature increasing Arctic temps 2 xs global rate Ocean
temperatures increasing Sea level rise Thermal expansion Melting
ice caps & glaciers Arctic sea ice decreasing # of intense
tropical cyclones Water vapor in atmosphere Changes in
precipitation amounts Figures 8-46a & b
Slide 33
Global Climate Change Evidence of current global warming
(cont.) Concentrations of carbon dioxide correlated with
temperature Carbon dioxide concentrations correlate with increased
anthropogenic greenhouse gases Carbon dioxide increasing at a rate
faster than observed in last 800,000 years Figure 8-F
Slide 34
Global Climate Change Consequences of global warming Projected
climate in the upcoming century Climate will warm about 0.4F per
decade Changes will be greater than those during 20 th c. Estimated
temperature increase from 3.3F - 7.2F Sea level rise Stronger
tropical cyclones Increased precipitation Figure 8-47a
Slide 35
Global Climate Change Climate models General circulation models
(GCMs) Numerous assumptions Model accuracy Addressing global
warming Kyoto protocol Standards for new industrialized countries
Mitigating & adapting Figure 8-47b
Slide 36
Summary Climate is classified based on precipitation and
temperature There are six primary groups of world climates The
tropical humid climates exist at tropical latitudes and are
characterized by warm, constant temperatures and rainfall Dry
climates exist near the subtropics and are characterized by hot,
dry conditions Mild midlatitude climates constitute a transition
between warmer tropical climates and cold severe midlatitude
climates Mild midlatitude climates typically have long, hot summers
& mild winters, and have modest precipitation Severe
midlatitude climates only occur in the Northern Hemisphere Severe
midlatitude climates have long, cold winters and short summers, and
have large annual temperature ranges Polar climates receive little
insolation and are permanently cold and dry Highland climates
depend on elevation of mountainous terrain for their climate
characteristics Many paleoclimatology methods are used to
understand the Earths past climate There are several factors that
influence long-term climate change Global warming is related to the
increase in carbon dioxide release by humans