ch. 26.2 climate zones. three main climate zones on earth; tropical climates around the equator,...
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• Three main climate zones on earth; tropical climates around the equator, middle latitude climates, and polar climates.
Tropical ClimatesTropical Climates
• Avg. monthly temp. of at least 18o C year round.
• Different climates within climate zones based on annual precipitation.
• Tropical Rain Forest—within 5 to 10 degrees of the equator; dense vegetation, over 250 cm of rain a year, yearly temperature range of about 3 degrees C.
• Tropical Desert Climate—20 to 30 degrees N. and S. latitude; influenced by sinking, warming, dry air; annual rainfall less than 25 cm.
• Tropical Savanna Climate—between tropical rain forests and tropical deserts.
• Shifting precipitation belts result in wet summers and dry winters.
• Open grasslands with scattered trees and shrubs.
Polar ClimatesPolar Climates
• Average monthly temp. never higher than 10 degrees C.
• Occur between 55 degrees latitude and the poles.
• Subarctic Climate—between 55 and 65 degrees N. latitude.
• Yearly precipitation of 25 to 50 cm.
• Evergreen forests can grow due to low evaporation.
• Severe winters and short summers.
• Large annual temperature range.
• Tundra Climate—named for tundra vegetation…mosses, lichens, small flowering plants…no trees.
• Lower temperature range due to moderating influence of nearby oceans.
• Warmest months average only 4 degrees C.
• 25 cm precipitation yearly, mostly snow.
Middle Latitude ClimatesMiddle Latitude Climates
• Latitude ranges from contiguous United States to southern Canada. Uneven precipitation in different regions result in several different climates.
• Marine West-Coast Climate—40 to 60 degrees N. latitude in Pacific NW. Cool moist air from the ocean causes 60 to 150 cm precipitation. Temp. range from 7 to 20 degree C.
• Mediterranean Climate—between 30 and 40 degrees latitude. Wet winters and dry summers. 40 cm avg. precipitation. Temp. range from 14 to 21 degrees C.
• Middle-Latitude Desert—less than 25 cm precipitation, and cold winters. Shrubs and cacti. 35 to 50 degrees N. latitude.
• Steppe Climate—same latitude as mid latitude deserts, but at higher elevations. 25 to 50 cm precipitation / yr. Grass type vegetation, and high temp. range.
• Humid Continental—warm humid summers with very cold winters. Violent weather conditions due to colliding air masses.
• Humid Subtropical—influenced by moist ocean air in summer. Heavy rains and hurricanes. Southeast USA.