Ch. 21 Climate

21.1 Factors That Affect Climate

Factors that Affect Climate Affect the 2 most important elements of climate Temperature & Precipitation Latitude Elevation Topography Water Bodies Atmospheric Circulation Vegetation

Latitude Distance N or S of the equator As latitude increases, the intensity of solar energy decrease The sun’s rays are most intense in the tropics why…bc the region is at a right angle to the sun Tropical Zones Temperate Zones Polar Zones

Elevation Height above sea level Air temp. decreases w/ elevation The higher the elevation is, the colder the climate is Elevation also determines how much precipitation an area gets

Topography Topographic features such as mountains play an important role in the amount of precipitation that falls over an area. Rain Shadows – the dry area on the leeward side of the mountain

Water Bodies Large bodies of water such as lakes & oceans have an important effect on the temp. of an area bc the temp. of the water body influences the temp. of the air above it Think back to last unit…how does land heat & cool differently than water?????

Atmospheric Circulation Global winds influence climate bc they distribute heat & moisture around the Earth HEAT BALANCE Warm air to the poles & cool air to the equator

Vegetation Certain types of plants only can grow in particular climates Vegetation can affect both temp. & precipitation patterns in a particular area Vegetation influences how much of the sun’s energy is absorbed & how fast this energy is released (affects temp.) Transpiration (influences precipitation)

REVIEW REVIEW REVIEW How does latitude affect climate? How does elevation affect climate? How does a mountain range affect climate? How do bodies of water affect climate? What effect do global winds have on climate? Describe how vegetation affects climate?

21.2 World Climates

The Koppen Climate Classification System Uses mean monthly & annual values of temp. and precipitation to classify climates Classifies it into climate regions 5 principle groups: humid tropical, dry climates, humid mid-latitude, polar climates, & highland climates

Humid Tropical Climates Climates without winters Every month has a mean temp. above 18 oC Amt. of precipitation exceeds 200 cm 2 types of humid tropical climates: Wet Tropical Tropical Wet & Dry

Humid Tropical Climates Wet Tropical Tropical Wet & Dry Tropical Rainforest High temps. & a lot of precipitation Sun’s rays are always high Winds blow over causing the warm, humid unstable air to rise cool and condense and then fall as precipitation Bordering the wet tropics Have temps. & total precipitation close to those in wet tropics, but this climate experiences times of low precipitation

Humid Mid-Latitude Climates Include climates with mild winters & severe winters Climates with mild winters have an avg. temp. in the coldest month that is below 18 oC but above -3 oC Severe winters have an avg. temp. in the coldest month that is below -3 oC

Humid Mid – Latitude w/ Mild Winters 3 types: humid subtropical, marine west coast, & dry-summer subtropical Humid subtropical – 25-40 degrees latitude on the Eastern side of the continent Marine West Coast – 40-65 degrees latitude N & S Dry-Summer Subtropical – 30-45 degrees latitude

Humid Mid-Latitude w/ Severe Winters 2 types: humid continental climates & subarctic climates Continental landmasses strongly influence both climates Absent in the Southern Hemisphere

Dry Climates Yearly precipitation is not as great as the potential loss of water by evaporation Evaporation is dependent on temperature 2 types of dry climates: arid or desert & semi-arid or steppe Result of global distribution of air pressure and winds

Polar Climates Mean temp. of the warmest month is below 10 oC Very little precipitation Evaporation rates are also low 2 types: Tundra Climate & Ice Cap Climate Tundra is a treeless region most in N. Hemisphere Ice Cap Climate does not have a single monthly mean above 0 oC & has little vegetation & permanent ice and snow

Highland Climates Localized (much different from climates in surrounding areas) Vary from place to place In general they are cooler & wetter than nearby areas at lower elevations

REVIEW REVIEW REVIEW Describe the Koppen climate classification system. How do highland climates compare with nearby lowlands? Can tundra climates exist at low latitudes? Why or why not?