visualizing physical geography copyright © 2008 john wiley and sons publishers inc. chapter 7...

Visualizing Physical GeographyCopyright © 2008 John Wiley and Sons Publishers Inc.

Chapter 7Global Climates


Chapter Overview

Keys to Climate

Climate Classification

Low-Latitude climates (Group I)

Midlatitude Climates (Group II)

High-Latitude Climates (Group III)

Objectives

Describe how temperature and precipitation affect climate.

Explain how climographs are related to climate groups.


Objectives

Describe the features of low, mid, and high-latitude climates.

Discuss the climate groups found in low, mid, and high-latitude climates



Keys to Climate

Temperature Regimes

Climate: the annual cycle of prevailing weather conditions at a given place, based on statistics taken over a long period

What determines temperature?

1. LatitudeVariation in insolationTemperature

2. Location—maritime or continental—moderates that variation


Keys to Climate

Global precipitation regions:1. Wet equatorial belt 2. Trade-wind coasts3. Tropical deserts and steppes 4. Midlatitude deserts 5. Moist subtropical regions 6. Midlatitude west coasts7. Arctic and polar deserts


Keys to Climate

Global Precipitation

Seasonal precipitation patterns:

1. Uniformly distributed

2. Summer precipitation maximum

3. Winter precipitation maximum



Air Mass Source Regions

Group I: Low-Latitude Climates

Group II: Midlatitude Climates

Group III: High-Latitude Climates


Climate ClassificationDry and Moist Climates

• Dry Climates: total annual evaporation>annual precipitation•Semiarid (steppe)•Arid

• Moist Climates: enough rain to keep soil moist all year, sustain year- round flow of larger streams

•Support forests or prairies• Wet-dry Climates: alternate wet and dry seasons



Highland Climates

• Usually cool •Temperatures decrease with altitude

• Usually Moist•Orographic precipitation



Climograph: graph on which two or more climate variables are plotted for each month of the year



Seasonal Precipitation Patterns

•Equatorial regions: wet all year

•Trade winds bring rain to equatorial/tropical east coasts

•Tropical deserts underlie subtropical high pressure cells•Eastern sides of midlatitude continents: warm moist air from western sides of subtropical highs•Midlatitude west coasts: subtropical highs block rainfall in summer



Temperature Patterns

• Latitude: temperatures drop from equator to poles

• Location: continental interiors have greater range in temperature than coastal regions

• Elevation: temperatures drop with elevation



Four low-latitude climates:

1. Wet equatorial 2. Monsoon and trade-wind coastal

3. Wet-dry tropical 4. Dry tropical



1.Wet Equatorial Climate: moist climate of the equatorial zone with a large annual water surplus and uniformly warm temperatures through the year• Controlled by ITCZ• Warm, moist mE and mT air masses• Heavy convectional rainfall• Uniform temperatures through the year• Low-latitude rainforests



2. Monsoon and trade-wind coastal climate: moist climate of low latitudes showing a strong rainfall peak in summer and short period of reduced rainfall in low-sun season• Abundant rainfall• Strong seasonal pattern• Monsoon winds bring moist air to west coasts• Trade winds bring moist air to east coasts• Low-latitude rainforests



3. Wet-dry tropical climate: climate of the tropical zone characterized by a very wet season alternating with a very dry season• Very dry season at low sun

• ITCZ is far away• Very wet season at high sun

• ITCZ is nearby• Savanna vegetation



4. Dry Tropical Climate: climate of the tropical zone with high temperatures and low rainfall.

• Center and east sides of subtropical high pressure cells• Extreme heat, large daily temperature range• Generally between 15º and 25º N and S• Arid deserts and semiarid steppes



Six midlatitude climates:5. Dry Subtropical 6. Moist Subtropical7. Mediterranean 8. Marine West-coast9. Dry midlatitude 10. Moist Continental



5. Dry Subtropical Climate: dry climate of the subtropical zone, transitional between the dry tropical climate and the dry midlatitude climate

• Poleward extension of dry tropical climate• High annual temperature range • Arid and semiarid subtypes



6. Moist Subtropical Climate: moist climate of the subtropical zone, characterized by a moderate to large annual water surplus and a strong seasonal temperature cycle

• Eastern sides of continents, between 20º and 35º N and S• mT air from western side of subtropical high pressure cells• Warm humid summers, abundant rainfall• Mild winters, ample rainfall• Forest vegetation



7. Mediterranean Climate: climate type of the subtropical zone, characterized by the alternation of a very dry summer and a mild, rainy winter

• Wet winter, dry summer• West coast of continents• Located between 30º and 45º N and S• Vegetation: shrubs and trees with hard leaves to resist water loss

(sclerophylls)



8. Marine West-Coast Climate: Cool, moist climate of west coasts in the midlatitude zone, usually with abundant precipitation and a distinct winter precipitation maximum

• Abundant precipitation, winter maximum• Frequent cyclonic storms• Mild winters, low annual temperature range• West coasts, between 35º and 60º N and S



9. Dry Midlatitude Climate: dry climate of the midlatitude zone with a strong annual temperature cycle and cold winters

• Interior of North America and Eurasia• Within the rainshadow of mountain ranges• Large annual temperature range• Arid and semiarid, desert and steppe



10. Moist Continental Climate: moist climate of midlatitude zone with strongly defined winter and summer seasons and adequate precipitation throughout the year

• Cold winters, warm summers• Located in the polar-front zone• Ample precipitation• Forests and tall grasslands



Three high-latitude climates:11. Boreal Forest 12. Tundra 13. Ice Sheet



11. Boreal Forest Climate: Cold climate of the subarctic zone in the northern hemisphere with long, extremely severe winters and several consecutive months of frozen ground• Long cold winters, short, cool summers• Source region for cP air masses• Greatest range of temperature• Boreal forests--needeleaf



12. Tundra Climate: Cold climate of the arctic zone with eight or more months of frozen ground• Polar and arctic air masses• Permafrost below surface• Saturated soil in summer• Tundra vegetation—low herbs and shrubs



13. Ice sheet climate: Severely cold climate found on the Greenland and Antarctic ice sheets

• Arctic and Antarctic air masses• Mean temperature below freezing all months• Low precipitation, high winds

visualizing physical geography copyright © 2008 john wiley and sons publishers inc. chapter 7...

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