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Title Page Photo
““I've lived in good climate, and it bores the hell I've lived in good climate, and it bores the hell out of me. I like weather rather than climate.”out of me. I like weather rather than climate.”
——John Steinbeck (Brainquote.com)John Steinbeck (Brainquote.com)
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Climate Classification• The Purpose of Classifying Climates
– To understand distribution of climates– To compare climates of different places
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• The Early Greek Classification Schemes– Greeks
• Temperature and latitude
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– Major climate zones of the Old World, as recognized today1) Equatorial warm wet2) Tropical hot dry3) Subtropical warm temperate4) Midlatitude cool temperate5) High-latitude cold
– Fig. 8-2
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The Köppen Classification System• Empirical System
– Has a numerical basis• Temperature data• Precipitation data
• Teaching tool– Simple to comprehend and to use– Shows an orderly pattern over the world– Gives some indication of climate origin (genesis)
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• Modified Köppen System– Five major climate groups
• Groups A, B, C, D, and E– 14 individual climate types
• Special category of highland (H) climate
– Fig. 8-3
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– Climatic Regions of the World
• Fig. 8-4
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Tropical Humid Climates (Group A)• Distribution of A Climates
– Within 0–25º of equator
• Fig. 8-6
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• Fig. 8-8
• Distinctive Features of A Climates– Average daily temperature greater than annual
temperature range
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– No true winter• “Winter” in tropics refers to the “low-sun” half of the year
“Summer” refers to the “high-sun” half of the year
– High temperatures prevail every month• A climates are distinguished by the monthly pattern of
rainfall– f = year-around rainfall– m = year-round rainfall, but with a brief drier period– w = wet summer and dry winter
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Tropical Wet Climate (Af)• Main locations
– Within 5–10º of equator – Amazon basin– Northern Congo basin– Islands of East Indies
• Characteristics─ Monotonous (“seasonless”)
“Night is the season of the tropics”─ High humidity─ Afternoon convective thundershowers─ High annual rainfall, evenly distributed during year
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• Dominant Controls– ITCZ influence entire year
• Animated Drawing (toggle forward-back-forward)
Convectiveprecipitation
30ºN30ºS
0º 10ºS10ºN
cTNH summerwet season
TradesTrades
SH winterdry season
cT
NH winterdry season
Trades Trades
SH summerWet season
Af
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• Climographs
– Fig. 8-7
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• Main locations– 5–25º of latitude– Most extensive of A climates – Adjacent to Af climates– Most widespread in Africa, South America– South Asia and northern Southeast Asia– Northern Australia• Characteristics
• Clear-cut seasonal alternation of wet and dry periods• Lower precipitation than other A climates
Tropical Savanna (AW)
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• Dominant Controls– ITCZ dominates during summer – cT or cP air mass dominates during winter
• Fig. 8-11
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• Climographs
– Fig. 8-10
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Tropical Monsoon (AM)• Main locations
– Coastal regions– Most prominent area is west-facing coasts of
India, southeastern Asia– Smaller areas scattered in tropical latitudes
• Characteristics– Very high rainfall totals in summer– Brief (1-4 months), drier period in winter
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• Dominant Controls– ITCZ movement– Jet Stream fluctuation– Continental pressure changes
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• Climographs
– Fig. 8-12
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Dry Climates (Group B)– Fig. 8-14
• Distribution of B Climates– Subtropical Dry Climates within 20–35º of latitude– Midlatitude Dry Climates within 35-55º of latitude
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• Distinctive Features of B climates– Cover 30% of the total land area of the world
• More area than any other climate group
– Dry conditions prevail all year• Potential evapotranspiration is greater than precipitation
– Two main sub-types based on precipitation• BW is extremely arid (desert)• BS is steppe (semi-arid)
– The two sub-types are further subdivided based on temperature• h is for the hot subtropical desert (BWh, BSh)• k is for the cold midlatitude desert (BWk, BSk)
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Subtropical Desert (BWh)• Main locations
– Centered at latitudes 25–30º– Western sides of continents,
including coasts• Extend into continental interiors
– Northern Hemisphere• Sonora-Colorado• Sahara• Arabian
– Southern Hemisphere• Peru-Atacama• Kalahari-Namib
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• Characteristics– Precipitation: extremely arid
• Scarce (most nearly rainless regions on Earth)• Unreliable (extremely long periods without rain)• Intense (brief, but heavy convective downpours)
– Very hot summers– Enormous daily temperature range– Coastal equatorward extensions: advection fog
off-shore
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• Dominant Controls– Subsidence from subtropical highs (STHs)
• Fig. 8-15
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– Cold ocean currents• Equatorward extensions
– Fig. 8-17
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• Cool, foggy west coast deserts
– Fig. 8-18
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• Climographs
– Fig. 8-16
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Subtropical Steppe (BSh)• Main locations
– Fringing BWh except on west coasts
• Characteristics– Similar to BWh but more moderate– Precipitation: semiarid
• Dominant Controls• Similar to BWh
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• Climographs
– Fig. 8-20
(Richard A. Crooker photos)
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Midlatitude Desert (BWk)• Main locations
– Central Asia– Western interior
of United States– Patagonia
– Fig. 8-14
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• Characteristics– Precipitation meager
• Erratic, mostly showery• Some winter snow
– Temperatures• Hot summers, cold winters• Very large annual temperature range• Large daily temperature range
• Dominant Controls– Rain shadow effects– Distance from sources of moisture
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• Climographs
– Fig. 8-21
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Midlatitude Steppe (BSk)• Main locations
– Fringing BWk
• Characteristics– Similar to BWk
(more moderate)– Precipitation:
semiarid
• Dominant Controls– Similar to BWk
– Fig. 8-14
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• Climographs
– Fig. 8-22
Photograph Source: U.S. Geological Surveyhttp://www.usgs.gov/125/articles/conservation.html
Photo: U.S. Great Plains, South Dakota
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Mild Midlatitude Climates (Group C)– Fig. 8-23
• Distribution of C Climates– Equatorward margin of the middle latitudes– Within 25-40º of latitude with some poleward
extensions
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• Distinctive Features of C climates– Temperatures
• Long summers, usually hot• Short winters, relatively mild
– Precipitation• No year-round moisture deficiency• Some climates have seasonal shortages
– Three subtypes• Mediterranean (Csa, Csb)• Humid subtropical (Cfa)• Marine west coast (Cfb, Cfc)
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Mediterranean Climates (Csa, Csb)• Main locations
– Western side of continents• 30–40º of latitude
– Mediterranean coast– California– Central Chile– Southern tip of Africa (Cape Town)– Australia (Perth & Adelaide)
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• Characteristics– Mild, wet winters, dry summers– Two sub-types based on summer temperatures
• a – hot summer (interior location)• b – cool/mild summer (coastal location)
• Fig. 8-26
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• Dominant Controls– STH subsidence in summer (forces cyclonic
storms poleward)– Westerly winds and cyclonic storms shift
equatorward in winter
– Precipitation• Moderate annually• Winter maximum (midlatitude cyclonic storms)
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• Climographs
– Fig. 8-24
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Humid Subtropical (Cfa, Cwa)• Main locations
– Eastern sides of continents• 25–30º of latitude
– Southeastern United States– Eastern China– Southern Brazil and Uruguay– Small areas in Africa and Australia
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• Characteristics– Temperatures
• Summers, warm to hot• Winters, mild to cold
– Precipitation• Abundant, mostly as rain• Summer maximum
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• Climographs
– Fig. 8-27
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Marine West Coast• Main locations
– Western sides of continents, mainly• 40–65º
– Western and central Europe• Largest area
– North America• Oregon to Alaska
– New Zealand and eastern Australia
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• Characteristics– Temperature
• Very mild winters for latitude
– Precipitation• Moderate to abundant, mostly in winter• Many rainy days• Much cloudiness
• Dominant Controls– Westerly flow and oceanic influence year-round
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• Climographs
– Fig. 8-30
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Severe Midlatitude Climates (Group D)– Fig. 8-31
• Distribution of D Climates– Only in Northern Hemisphere– Within 35–70º of latitude
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• Distinctive Features of D climates– Temperatures
• Large annual temperature range– Continentality
• Cold winter, relatively short summer
– Precipitation• Summer maxima• Abundant to meager amounts• Diminishes toward inland and poleward
– Two Main Subtypes• Humid Continental• Subarctic
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Humid Continental (Dfa, Dfb, Dwa, Dwb)• Location
– N. Hemisphere only– 35–55º of latitude– Eastern sides of continents
– Fig. 8-31
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• Characteristics– Temperature
• Warm/hot summers• Large annual temperature range
– Precipitation• Moderate to abundant• Summer maxima
• Dominant Controls– Westerly winds and storms
• Midlatitude cyclones in winter in North America• Monsoons in Asia
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• Climographs
– Fig. 8-32
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Sub Arctic (Dfc, Dfd, Dwc, Dwd)
• Location– Northern Hemisphere only– Latitudes 50–70º– Across North American and Eurasia
• Characteristics– Temperature
• Long, dark, very cold winters• Brief, mild summers• Enormous annual temperature range
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– Precipitation• Meager• Summer maxima• Light snow in winter, little melting
• Dominant Controls– Pronounced continentality– Alternating…
• Westerlies and cyclonic storms• Prominent anticylcones
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• Climographs
– Fig. 8-35
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Polar Climates (Group E)
• Distribution of E Climates– Poleward of 70º of latitude
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• Distinctive Characteristics– Temperatures
• Coldest summers• Lowest annual average• Large annual temperature range• Small daily temperature range
– Extraordinarily dry• Low precipitating, mostly snow• Evaporation is nil
– Two subtypes• Tundra• Ice Cap
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Tundra (ET)• Main Locations
– Fringes of Arctic Ocean– Small coastal areas in Antarctica
• Fig. 8-36
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• Characteristics– Temperature
• Long, cold dark winters• Brief, cool summers
– Precipitation• Very sparse• Mostly snow
• Dominant Controls– Latitude– Distance from sources of heat and moisture– Extreme seasonal contrasts in sunlight/darkness– Polar anticyclones (A and cP air masses)
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• Climographs
– Fig. 8-37
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Ice Cape (EF)• Location
– Antarctica– Greenland
• Characteristics– Temperature
• Long, cold, dark winters
• Cold, windy summers
– Precipitation• Very sparse, all
snow
• Fig. 8-36
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• Dominant Controls– Latitude– Distances from sources of heat and moisture– Extreme seasonal contrasts in sunlight/darkness– Polar anticyclones (A and cP air masses)
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• Climographs
– Fig. 8-38
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Highland Climate (Group H)• Locations
– High uplands (mountains and plateaus)
– Fig. 8-40
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• Characteristics– Complex local variation in small areas– Vertical climate zonation
– Fig. 8-42
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– Changeability of weather– Fig. 8-43
• Dominant Controls– Altitude– Slope aspect and slope angle
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• Climographs
– Fig. 8-41
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Global Patterns Idealized• General Models of the Climate Distribution
– Idealized seasonal precipitation patterns and climates along the west coasts of continents (Fig. 8-44).
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– Idealized Global Pattern
– Fig. 8-45
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• Climatic Distribution in Africa: A Practically Perfect Example
– Fig. 8-45 and Fig. 8-46
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• The modified Köppen system recognizes six major climatic zones:1. Tropical humid (A)2. Dry (B)3. Mild midlatitude (C)4. Severe midlatitude (D)5. Polar (E)6. Highland (H)
• A model of climate distribution on a hypothetical continent helps use predict what the climate should be like at a particular location.