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Climatic Zones & TypesClimatic Zones & Types

Part IIPart II

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 SteinbeckJohn Steinbeck

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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)

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Dominant Controls

– STH subsidence in summer (forces cyclonic

storms pole-ward)

– Westerly winds and cyclonic storms shift

equator-ward in winter

– Precipitation

• Moderate annually

• Winter maximum (midlatitude cyclonic storms)

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Climographs

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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

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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

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Severe Midlatitude Climates (Group D)

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 pole-ward

– 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

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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

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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

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Polar Climates (Group E)

Distribution of E Climates

– Pole-ward 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

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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

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Ice Cape (EF) Location

– Antarctica

– Greenland

Characteristics

– Temperature

• Long, cold, dark winters

• Cold, windy summers

– Precipitation

Very sparse, all snow

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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

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Highland Climate (Group H)

Locations High uplands (mountains and plateaus)

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Characteristics – Complex local variation in small areas

– Vertical climate zonation

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Changeability of weather

Dominant Controls

– Altitude

– Slope aspect and slope angle

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Climographs

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Global Patterns Idealized

General Models of Climate Distribution

• Idealized seasonal

precipitation patterns and

climates along the west

coasts of continents.

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Idealized Global Pattern

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Climatic Distribution in Africa:

A Practically Perfect Example

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Global Climate Change

• Time scale of observations determine what

patterns of change stand out in the record

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Determining Climates of the Past

Animation (End of the Last Ice Age)

– Dendrochronology

– Oxygen isotope analysis of oceanic sediments

– Ice cores

– Pollen analysis

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Causes of Long-Term Climate Change

Animation (Orbital Variations and Climate Change)

– Volcanic activity and meteor impacts

– Fluctuations in orbital output

– Variations in Earth-Sun relations

– Greenhouse gas concentrations

– Feedback mechanisms

– The roles of the ocean

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Climate Models

– Climate prediction

– Global Circulation Models (GCMs)

• Mathematical models of Earth’s climate system

• Computer simulation models of future climates (3)

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• The fundamental geographic aspect of

climate is its global distribution.

• The modified Köppen classification system

is widely used for its pedagogic value.

• The basis of the Köppen system is

temperatures and precipitation amounts and

patterns.

Summary

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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 us predict what the climate should be like at a particular location.