Download File

22-1
Factors that Affect Climate
Climate: established pattern of weather over a long
period of time.
Weather: Day to day variations of the condition of the
atmosphere.
Climates are described by using the average yearly, daily,
or monthly:
1) Temperature
2) Precipitation
Temp and Precip ranges are also used (difference
between avg low and high)
Extremes, averages, and ranges must be taken into
account to be reliable in describing climate.
So what influences these temperatures and
precipitation?
1. Latitude
2. Heat absorption and release
3. Topography
1. LATITUDE
Solar Energy: The higher the latitude, the less solar
energy is absorbed by the planet.
The tilt of Earth’s axis is also important (seasons)
Belts of air at different densities result from this
unequal heating of Earth.
Global Wind Patterns: cool, dense air at poles----warm,
light air at equator
Cool air is high pressure/Warm air is low pressure (These
differences create WIND)
Wind Belts
 Doldrums (0o-20o) : near equator, air rises-coolsexpands, large amounts of precipitation
 Subtropical Highs (20o-30o): air sinks, warms,
lowers humidity, little precipitation (deserts)
 Subpolar Lows (45o-60o): frequent cyclones and
other severe storms (helps to form polar front)
2. HEAT ABSORPTION and BALANCE
Different areas absorb/release heat differently. (land
faster than water)
So, the air temps over these areas affect the climate.
 Specific heat and evaporation----Water has high
specific heat (heat required to raise 1 gram of
water 1 oC) Need lots of heat to warm water.
 Ocean Currents---winds blow toward shore,
then these sea breezes can affect land climate.
El Nino-Southern Oscillation (ENSO)—cycle of changing
wind and water current patterns in the Pacific Ocean.
Every 3-10 years El Nino causes surface water temps
along coast of South America to rise—this causes an
increase in severe storms in the Pacific.
El Nino has a cool water phase--La Nina (increases
amount of Atlantic Hurricanes).
Seasonal Winds (monsoons): Temp differences between
land and ocean causes wind to shift seasonally.
Winter—land to ocean
Summer—ocean to land
3. TOPOGRAPHY
Surface features (mountains, valleys) also influence
climate.
 Elevation (high elevation—low temps)
 Rain Shadows (air mass moisture lost as
precipitation as it “climbs” upslope on a
mountain) ---other side of mountain
experiences dry, warm air.
o This dry wind that goes “downslope” is
called a foehn in the Alps, a chinook in the
Rockies.