Chapter 13: Global Chapter 13: Global ClimateClimate

A world with many climatesA world with many climates Climatic classification - the Köppen Climatic classification - the Köppen

systemsystem The global pattern of climateThe global pattern of climate

Global TemperaturesGlobal Temperatures controls on temperature climatology:controls on temperature climatology:

- intensity of sunshine and its variation with latitude- intensity of sunshine and its variation with latitude- distribution of land and water and ocean currents- distribution of land and water and ocean currents- prevailing winds- prevailing winds- location of high and low pressure areas- location of high and low pressure areas- mountain barriers and altitude- mountain barriers and altitude

Q1: Why is the Antarctic in the next slide not so cold? becausea) winter and summer average outb) Antarctic is actually not too cold compared to Arcticc) only the equivalent sea-level temperature is shownd) Arctic is simply colder

Q2: where is the hottest place on earth?a) subtropical desert; b) equatorial ocean; c) equatorial land; d) midlatitudes

Fig. 13-1, p. 355

Average annual sea-level temperature

Global PrecipitationGlobal Precipitation relationship to areas of rising and sinking airrelationship to areas of rising and sinking air

influence of ITCZinfluence of ITCZ influence of orographic uplift and rain shadowsinfluence of orographic uplift and rain shadows

• Precipitation is most abundant where air rises,Precipitation is most abundant where air rises,and least abundant where it sinks.and least abundant where it sinks.

Q3: Why does snow still accumulate over Antarctic when the precipitation there is similar to that in the Sahara Desert? Becausea) altitude is high; b) it is cold c) evaporation/sublimation is even smaller than precipitation;d) katabatic wind is too strong

Q4: where are the wettest locations on earth?a) windward side of mountains; b) flat plainsc) leeward side of mountains; d) valleys

mm/month

Fig. 13-2, p. 356

Climatic Classification - the Climatic Classification - the Köppen System (1918)Köppen System (1918)

Tropical moist climatesTropical moist climates dry climatesdry climates moist midlatitude climates with mild wintersmoist midlatitude climates with mild winters moist midlatitude climates with severe wintersmoist midlatitude climates with severe winters polar climatespolar climates mountainsmountains criticisms of the Köppen climate classification system: sharp criticisms of the Köppen climate classification system: sharp

boundary between climatic zones due to the use of vegetation boundary between climatic zones due to the use of vegetation to represent monthly temperature and precipitation.to represent monthly temperature and precipitation.

Fig. 13-6, p. 361

The Global Pattern of The Global Pattern of ClimateClimate

Major features of Earth’s climate distribution (moist Major features of Earth’s climate distribution (moist tropical, dry, moist/mild winter, moist/severe winter, polar, tropical, dry, moist/mild winter, moist/severe winter, polar, highland)highland)

local variations within larger climate regionslocal variations within larger climate regions

Q5: Arizona climate belongs toa) semi-arid or steppe; b) tropical wet and dryc) moist climate with mild and dry winter

Q6: Florida climate belongs toa) semi-arid or steppe; b) tropical wet and dryc) humid subtropical with mild winter

Q7: Minnesota climate belongs to a) semi-arid or steppeb) humid subtropical with mild winterc) humid continental with severe winterd) moist tropical

Tropical Moist Climates Tropical Moist Climates tropical wet (Af): rainforest; small seasonal tropical wet (Af): rainforest; small seasonal

temperature variation; soil nutrients from temperature variation; soil nutrients from dead tree decompositiondead tree decomposition

tropical monsoon (Am): rainforest,tropical monsoon (Am): rainforest,

with 1-2 dry months with 1-2 dry months

Tropical Moist Climates Tropical Moist Climates tropical wet and dry (Aw): savanna; tropical wet and dry (Aw): savanna;

distinct dry season; larger seasonal distinct dry season; larger seasonal temperature variationtemperature variation

Q8: Why does max P occur in summer?a) ITCZ is located there in summer b) temperature is higherc) vegetation needs water in summerd) dust storm is less

Tropical Moist Climates Tropical Moist Climates tropical wet and dry (Aw): savanna; tropical wet and dry (Aw): savanna;

distinct dry season; larger seasonal distinct dry season; larger seasonal temperature variationtemperature variation

Q9: Why does max T occur in March?a) ITCZ is located there in March b) solar heating is strong with minimal cloudsc) dust storm is more frequent

Dry ClimatesDry Climates In general, minimal P, large T seasonal variation, high TIn general, minimal P, large T seasonal variation, high T arid (BW): most of the deserts in the world;arid (BW): most of the deserts in the world;

few deserts are completely barrenfew deserts are completely barrenQ10: What is the age of the cactus with arms in the figure?a) 0-20 yrs, b) 20-40 yrs, c) 40-60 yrs, d) > 60 yrs

Dry ClimatesDry Climates semiarid (BS) or steppe: most of western U.S. (including semiarid (BS) or steppe: most of western U.S. (including

Tucson); grass or shrubsTucson); grass or shrubs

Q11: is it possible to have coastal deserts with clouds and drizzles in the world?a) yes; b) no

Moist Subtropical Mid-Latitude Moist Subtropical Mid-Latitude ClimatesClimates

humid with mild winters; relatively large T variationhumid with mild winters; relatively large T variation humid subtropical (CfA): SE U.S.; small P seasonal variationhumid subtropical (CfA): SE U.S.; small P seasonal variation (west coast) marine (CfB): cool summer(west coast) marine (CfB): cool summer

Moist Subtropical Mid-Latitude Moist Subtropical Mid-Latitude ClimatesClimates

Mediterranean (Cs): dry summer; western coast of U.S.; Mediterranean (Cs): dry summer; western coast of U.S.; coastal areas of the Mediterranean Seacoastal areas of the Mediterranean Sea

coastalCs

interiorCs

Q12: why is summer so dry in San Francisco? a) subtropical high; b) foggy weather, c) cold temperature, d) cloudy sky

Moist Subtropical Mid-Latitude Moist Subtropical Mid-Latitude ClimatesClimates

Mediterranean (Cs):Mediterranean (Cs):

Vegetation type: chaparral (includes Chamise, manzanita, and foothill pine)

Moist Continental Climates Moist Continental Climates with Severe Winterwith Severe Winter

Hot summerDfa

Cool summer SubpolarDfb Dfc

Polar Polar ClimatesClimates

ice caps (EF)ice caps (EF)

Tundra (ET)

Highland ClimatesHighland Climates altitude effects are similar to latitude effects: altitude effects are similar to latitude effects:

100 m elevation difference ~ 1 deg in horizontal distance100 m elevation difference ~ 1 deg in horizontal distance

Across central Sierra Nevada

Q13: Semi-arid regions usually havea) grassland and/or shrubland, b) forest, c) tundra

Q14: Mediterranean climate usually hasa) shrubland, b) grassland, c) chaparral, d) forest

Q15: Humid continental climate with severe winter and cool summer usually has

a) boreal forest, b) grassland, c) shrubs

Q16: Subpolar or polar climate usually hasa) forest, b) tundra