Chapter 9 The Global Scope of Climateudel.edu/~ginah/geog101/chapter9and10.pdf · Air temperature and precipitation Climatic water balance `Terjung System Net radiation Energy balance.

Chapter 9Chapter 9The Global Scope of ClimateThe Global Scope of Climate

Climatic ClassificationClimatic Classification

LatitudeLatitude –– PolePole--toto--Equator temperature gradientEquator temperature gradientContinentalityContinentality –– Proximity to large bodies of Proximity to large bodies of waterwaterSeasonalitySeasonality –– Changes in patterns during the Changes in patterns during the annual cycleannual cycle

Climatic ClassificationClimatic Classification

A scheme for dividing the world into A scheme for dividing the world into characteristic climate typescharacteristic climate types

Begun with the Ancient GreeksBegun with the Ancient GreeksFrigid ZoneFrigid Zone (60°(60°--90°N)90°N)Temperate ZoneTemperate Zone (30°(30°--60°N)60°N)Torrid ZoneTorrid Zone ( 0°( 0°--30°N)30°N)

Climatic ClassificationClimatic ClassificationKöppenKöppen--GeigerGeiger--Pohl SystemPohl System

Air temperature and precipitationAir temperature and precipitationVegetation regimesVegetation regimes

Thornthwaite SystemThornthwaite SystemAir temperature and precipitationAir temperature and precipitationClimatic water balanceClimatic water balance

Terjung SystemTerjung SystemNet radiationNet radiationEnergy balanceEnergy balance

KöppenKöppen--GeigerGeiger--Pohl SystemPohl System

The Climatic Water BalanceThe Climatic Water Balance

A system of water accountingA system of water accountingInput: PrecipitationInput: Precipitation


A system of water accountingA system of water accountingOutput: EvaporationOutput: Evaporation


A system of water accountingA system of water accounting

EvaporationEvaporation –– process by which water process by which water becomes a gasbecomes a gas


A system of water accountingA system of water accountingOutput: TranspirationOutput: Transpiration



EvaporationEvaporation –– process by which water process by which water becomes a gasbecomes a gasTranspirationTranspiration –– evaporative loss of water to evaporative loss of water to the atmosphere through the stomata of the atmosphere through the stomata of leavesleaves



EvapotranspirationEvapotranspiration –– combined loss of water to combined loss of water to the atmosphere by the atmosphere by evaporationevaporation from the soil and from the soil and transpirationtranspiration from plantsfrom plants

The Climatic Water BalanceThe Climatic Water BalanceA system of water accountingA system of water accountingOutput: EvapotranspirationOutput: Evapotranspiration

The Climatic Water BalanceThe Climatic Water BalanceA system of water accountingA system of water accountingOutput: Runoff/StreamflowOutput: Runoff/Streamflow

The Climatic Water BalanceThe Climatic Water BalanceA system of water accountingA system of water accounting

P = ET + RP = ET + R


Potential EvapotranspirationPotential EvapotranspirationIdeal rate of evapotranspiration that occurs when a Ideal rate of evapotranspiration that occurs when a complete canopy of growing plants is continuously complete canopy of growing plants is continuously supplied with all the soil water they need.supplied with all the soil water they need.


Potential EvapotranspirationPotential EvapotranspirationIs largely a function of air temperatureIs largely a function of air temperatureGreatest in the tropics; Least at the polesGreatest in the tropics; Least at the poles


PrecipitationPrecipitationMoisture SupplyMoisture Supply

vs.vs.Potential EvapotranspirationPotential Evapotranspiration

Moisture DemandMoisture Demand

The Climatic Water Balance The Climatic Water Balance Classification of ClimateClassification of Climate

LatitudeLatitudeLowLow--latitude Climateslatitude Climates ( 0°( 0°--30°N) 30°N) –– 44MidMid--latitude Climateslatitude Climates (30°(30°--60°N) 60°N) –– 66HighHigh--latitude Climateslatitude Climates (60°(60°--90°N) 90°N) –– 33

Seasonal Supply vs. DemandSeasonal Supply vs. DemandSeasonalitySeasonalityContinentalityContinentality

Chapter 10Chapter 10LowLow--Latitude ClimatesLatitude Climates

LowLow--Latitude ClimatesLatitude Climates

Dominated by theDominated by thecirculation of the Hadley Cellscirculation of the Hadley Cells


Dominated by theDominated by thecirculation of the Hadley Cellscirculation of the Hadley Cellsseasonal migration of the ITCZseasonal migration of the ITCZ


Dominated by theDominated by thecirculation of the Hadley Cellscirculation of the Hadley Cellsseasonal migration of the ITCZseasonal migration of the ITCZprevailing easterly trade windsprevailing easterly trade winds


Dominated by theDominated by thecirculation of the Hadley Cellscirculation of the Hadley Cellsseasonal migration of the ITCZseasonal migration of the ITCZprevailing easterly trade windsprevailing easterly trade winds

Characterized by a relatively uniform air Characterized by a relatively uniform air temperature regime all year longtemperature regime all year long

Consequently, potential evapotranspiration is Consequently, potential evapotranspiration is nearly constant all year longnearly constant all year long

Potential Evapotranspiration Potential Evapotranspiration –– LowLow--LatitudesLatitudes

1) Wet Equatorial Climate1) Wet Equatorial Climate

Associated with the ITCZ all year longAssociated with the ITCZ all year longmE air mass dominates, some mTmE air mass dominates, some mTRainfall is plentiful during the entire yearRainfall is plentiful during the entire year

Annual total exceeds 250 cmAnnual total exceeds 250 cmAir temperature is relatively uniformAir temperature is relatively uniform

Mean air temperature near 27°CMean air temperature near 27°C

Wet Equatorial ClimateWet Equatorial Climate

Wet Equatorial Climate Wet Equatorial Climate Iquitos, Peru Iquitos, Peru –– 3°S3°S

2) Dry Tropical Climate2) Dry Tropical Climate

Descending air of the Hadley CellDescending air of the Hadley CellSubSub--tropical High Pressure dominatestropical High Pressure dominatesLittle rainfall during the entire yearLittle rainfall during the entire year

Desert environmentDesert environmentAir temperature has a slight seasonal trendAir temperature has a slight seasonal trend

Greatest air temperatures during the highGreatest air temperatures during the high--sun seasonsun season

Dry Tropical ClimateDry Tropical Climate

Dry Tropical ClimateDry Tropical ClimateWadi Halfa, Sudan Wadi Halfa, Sudan ---- 22°N22°N

3) Tropical Wet & Dry Climate3) Tropical Wet & Dry Climate

Seasonal migration of the ITCZSeasonal migration of the ITCZSubSub--tropical High Pressure in lowtropical High Pressure in low--sun season; mE in sun season; mE in highhigh--sun seasonsun seasonMarked seasonal cycle to precipitationMarked seasonal cycle to precipitation

Precipitation “follows the sun”Precipitation “follows the sun”Air temperature has a slight seasonal trendAir temperature has a slight seasonal trend


Tropical Wet & Dry Climate (N.H.)Tropical Wet & Dry Climate (N.H.)

Tropical Wet & Dry Climate (S.H.)Tropical Wet & Dry Climate (S.H.)

Tropical Wet & Dry ClimateTropical Wet & Dry ClimateTimbo, Guinea Timbo, Guinea ---- 10°N10°N

Tropical Wet & Dry ClimateTropical Wet & Dry Climate

4) Trade4) Trade--Wind Coastal ClimateWind Coastal Climate

East coasts East coasts –– windward side of the continentwindward side of the continentMonsoon climate Monsoon climate –– wind shift during yearwind shift during yearMarked seasonal cycle to precipitationMarked seasonal cycle to precipitation

Precipitation “follows the sun”Precipitation “follows the sun”Air temperature has a slight seasonal trendAir temperature has a slight seasonal trend


TradeTrade--Wind Coastal Climate (N.H.)Wind Coastal Climate (N.H.)

TradeTrade--Wind Coastal Climate (S.H.)Wind Coastal Climate (S.H.)

TradeTrade--Wind Coastal ClimateWind Coastal ClimateBelize City, Belize, Sudan Belize City, Belize, Sudan ---- 17°N17°N

TradeTrade--Wind Coastal ClimateWind Coastal ClimateCochin, India Cochin, India ---- 10°N10°N


Chapter 11Chapter 11MidMid--Latitude andLatitude and

HighHigh--Latitude ClimatesLatitude Climates

The Climatic Water Balance The Climatic Water Balance Classification of ClimateClassification of Climate

LatitudeLatitudeLowLow--latitude Climateslatitude Climates ( 0°( 0°--30°N) 30°N) –– 44MidMid--latitude Climateslatitude Climates (30°(30°--60°N) 60°N) –– 66HighHigh--latitude Climateslatitude Climates (60°(60°--90°N) 90°N) –– 33

Seasonal Supply vs. DemandSeasonal Supply vs. DemandSeasonalitySeasonalityContinentalityContinentality

MidMid--Latitude ClimatesLatitude Climates


Dominated by the prevailing westerliesDominated by the prevailing westerliesPrimarily Northern Hemisphere climatesPrimarily Northern Hemisphere climatesWestWest--toto--east movement of cyclones and frontseast movement of cyclones and fronts

Latitude is a secondary factorLatitude is a secondary factorConsists of six climate typesConsists of six climate types

Three in the lower midThree in the lower mid--latitudes latitudes –– subtropicssubtropicsThree in the upper midThree in the upper mid--latitudeslatitudes


Potential Evapotranspiration Potential Evapotranspiration –– SubtropicsSubtropics

1) Dry Subtropical Climate1) Dry Subtropical Climate

Extension of the Dry Tropical climate into midExtension of the Dry Tropical climate into mid--latitudeslatitudesSource region for cT air massesSource region for cT air massesDistinct cool season occurs during winterDistinct cool season occurs during winterLow precipitation all year longLow precipitation all year long

Dry Subtropical ClimateDry Subtropical Climate

Dry Subtropical ClimateDry Subtropical Climate

Dry Subtropical ClimateDry Subtropical ClimateYuma, Arizona Yuma, Arizona –– 33°N33°N

2) Moist Subtropical Climate2) Moist Subtropical Climate

Flow of air from mT from the western edge of the Flow of air from mT from the western edge of the subtropical High pressuresubtropical High pressureStrong annual air temperature cycle with no winter Strong annual air temperature cycle with no winter month averaging below freezingmonth averaging below freezingAbundant rainfall all year long; cyclonic in winter, Abundant rainfall all year long; cyclonic in winter, convectional in summerconvectional in summerHigh humidityHigh humidity“Hurricane Coast”“Hurricane Coast”

Moist Subtropical ClimateMoist Subtropical Climate



Moist Subtropical ClimateMoist Subtropical Climate, Charleston, , Charleston, South Carolina South Carolina –– 33°N33°N


Effect of the Subtropical HighEffect of the Subtropical High

3) Mediterranean Climate3) Mediterranean Climate

Mediterranean ClimateMediterranean Climate

Dominated by the influence of cT air in summer, Dominated by the influence of cT air in summer, mT air in wintermT air in winterStrong High pressure offshore in summer deflects Strong High pressure offshore in summer deflects storm tracks to the northstorm tracks to the northModerate temperature range with warm to hot Moderate temperature range with warm to hot summers and mild winterssummers and mild wintersWet winter and dry summer Wet winter and dry summer SeasonalSeasonal


Mediterranean Climate Mediterranean Climate Monterey, Californa Monterey, Californa –– 36°N36°N


Subtropical ClimatesSubtropical Climates

Potential Evapotranspiration Potential Evapotranspiration –– Upper MidUpper Mid--latitudeslatitudes

Upper MidUpper Mid--Latitude ClimatesLatitude Climates

4) Marine West Coast Climate4) Marine West Coast Climate

Dominated by mP air masses and onshore flow of Dominated by mP air masses and onshore flow of moist air from the westerliesmoist air from the westerliesTemperature cycle moderated by marine influence Temperature cycle moderated by marine influence of warm, offshore ocean current of warm, offshore ocean current –– cool summers, cool summers, mild wintersmild wintersAbundant precipitation, often with a winter Abundant precipitation, often with a winter maximum and usually accentuated by orographic maximum and usually accentuated by orographic effectseffects

Marine West Coast ClimateMarine West Coast Climate

Marine West Coast ClimateMarine West Coast Climate

Marine West Coast ClimateMarine West Coast Climate,,Vancouver, British Columbia Vancouver, British Columbia –– 49°N49°N


5) Dry Midlatitude Climate5) Dry Midlatitude Climate

Dominated by dry cP air massesDominated by dry cP air massesStrong air temperature cycle with large annual Strong air temperature cycle with large annual range range –– summers are warm to hot, winters are cold summers are warm to hot, winters are cold and snowyand snowyLittle precipitation due to the rainshadow effect and Little precipitation due to the rainshadow effect and interior continental location interior continental location –– slight summer slight summer maximummaximum

Dry Midlatitude ClimateDry Midlatitude Climate

Dry Midlatitude ClimateDry Midlatitude Climate

Dry Midlatitude ClimateDry Midlatitude Climate,,Pueblo, Colorado Pueblo, Colorado –– 38°N38°N


6) Moist Continental Climate6) Moist Continental Climate

Dominated by frontal interactions between dry cP Dominated by frontal interactions between dry cP and moist mT air massesand moist mT air massesSummers warm, winters cold; relatively large Summers warm, winters cold; relatively large annual air temperature rangeannual air temperature rangeAmple precipitation with a slight summer maximum Ample precipitation with a slight summer maximum –– convective in summer; cyclonic in winterconvective in summer; cyclonic in winter

Moist Continental ClimateMoist Continental Climate


Moist Continental ClimateMoist Continental Climate,,Madison, Wisconsin Madison, Wisconsin –– 43°N43°N


Upper Midlatitude ClimatesUpper Midlatitude Climates


Midlatitude ClimatesMidlatitude Climates



Dominated by the Arctic Air MassDominated by the Arctic Air MassPrimarily Northern Hemisphere climatesPrimarily Northern Hemisphere climatesOne, however, is present in the Southern One, however, is present in the Southern Hemisphere Hemisphere –– in Antarctica (dominated by the in Antarctica (dominated by the Antarctic Air Mass)Antarctic Air Mass)


Dominated by the Arctic Air MassDominated by the Arctic Air MassPrimarily Northern Hemisphere climatesPrimarily Northern Hemisphere climatesAlso found along the tip of Antarctica near Chile Also found along the tip of Antarctica near Chile (dominated by Antarctic Air Mass)(dominated by Antarctic Air Mass)

Consists of only three climate types, stratified Consists of only three climate types, stratified primarily by latitude and proximity to the coastprimarily by latitude and proximity to the coast

Potential Evapotranspiration Potential Evapotranspiration –– HighHigh--LatitudesLatitudes

1) Continental Subarctic Climate1) Continental Subarctic Climate

Associated with Boreal Forest vegetationAssociated with Boreal Forest vegetationShort, cool summer Short, cool summer –– long, very cold winterlong, very cold winterGreatest Annual Air Temperature RangeGreatest Annual Air Temperature RangeSource region for cP air masses Source region for cP air masses –– located mainly in located mainly in the continental interiorsthe continental interiorsLittle rainfall, falling mostly in the summerLittle rainfall, falling mostly in the summer

Continental Subarctic ClimateContinental Subarctic Climate

Continental Subarctic Climate Continental Subarctic Climate Fort Vermillion, Alberta Fort Vermillion, Alberta –– 57°N57°N

Continental Subarctic Climate Continental Subarctic Climate

Continental Subarctic Climate Continental Subarctic Climate Yatkutsk, Russia Yatkutsk, Russia –– 61°N61°N

2) Tundra Climate2) Tundra Climate

Coastal Arctic fringe climateCoastal Arctic fringe climateMaritime influence keeps winter warmer than Maritime influence keeps winter warmer than Continental SubarcticContinental SubarcticVery short summer, very long winterVery short summer, very long winterLow annual precipitation totalLow annual precipitation total

Tundra ClimateTundra Climate

Tundra Climate Tundra Climate Upernivik, Greenland Upernivik, Greenland –– 73°N73°N

Tundra Climate Tundra Climate

Tundra Climate Tundra Climate Barrow Point, Alaska Barrow Point, Alaska –– 71°N71°N

3) Ice Sheet Climate3) Ice Sheet Climate

Source region for cA and cAA air massesSource region for cA and cAA air massesAll months are below freezing All months are below freezing –– no growthno growthLowest Global Air TemperaturesLowest Global Air TemperaturesPolar deserts Polar deserts –– very low precipitation totals although very low precipitation totals although snow accumulatessnow accumulates

Ice Sheet ClimateIce Sheet Climate



High Latitude ClimatesHigh Latitude Climates

Climate and Ocean CurrentsClimate and Ocean CurrentsHypothetical Northern Hemisphere ContinentHypothetical Northern Hemisphere Continent

Climate and Surface WindsClimate and Surface WindsHypothetical Northern Hemisphere ContinentHypothetical Northern Hemisphere Continent

Climate, Ocean Currents, and Surface WindsClimate, Ocean Currents, and Surface WindsHypothetical Northern Hemisphere ContinentHypothetical Northern Hemisphere Continent

Chapter 9 The Global Scope of Climateudel.edu/~ginah/geog101/chapter9and10.pdf · Air temperature and precipitation Climatic water balance `Terjung System Net radiation Energy balance.

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