Global Climates and Biomes
AP Environmental Science
Chapter 4
Get your brains working:
At the beginning of chapter 4,
there is a story about
climatic changes occurring in
Kenya during 2003. For
credit, take a couple minutes
and write down 1) what
these shifts were and 2) why
they mattered to the Kenyan
people.
Global processes determine weather
and climate
Weather: Short-term atmospheric conditions (minutes to days)
Climate: Long-term. Climate is the average weather that occurs
in a given region over a long period (typically several decades)
Earth’s Atmosphere
Earth’s atmosphere consists of
five layers of gasses.
Gravity keeps those layers in
place, but because gravity
weakens as you move away
from the plant, the layers near
the top are less dense than
those nearer the surface.
Ozone is primarily located
between the troposphere and
stratosphere
Unequal Heating of Earth
The unequal heating of Earth has three primary causes:
1) Variation in the angle at which the Sun’s rays strike Earth
2) Variation in the amount of surface area over which the Sun’s
rays are distributed
3) Some areas of Earth reflect more solar energy than others
Reason #1: Variation in the angle at
which the Sun’s rays strike Earth
Reason #2: Variation in the amount of surface
area over which the Sun’s rays are distributed
Reason #3: Some areas of Earth reflect more
solar energy than others
Atmospheric Convection Currents
Convection: Transfer of heat of heat via gas/liquid currents
Air has four properties that determine how it circulates in the
atmosphere: density, water vapor capacity, adiabatic
heating/cooling, and latent heat release
Density of air determines its movement: less dense air rises,
more dense air sinks
Water vapor capacity: maximum amount of vapor air can hold is
called the saturation point. As temperature falls, saturation
point falls. This is how clouds form and bring about
precipitation. As temperature increases, saturation point
increases.
Atmospheric Convection Currents
Adiabatic cooling: As air rises in the atmosphere, it expands due
to decreased pressure and it and cools
Adiabatic heating: As air sinks toward the surface pressure
increase and air warms
Latent heat: When water vapor condenses into liquid water,
heat is released. This means when water condenses, air will
become warmer and begin to rise.
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Convection currents: These are global patterns of air movement
that are initiated by this unequal heating of Earth
Hadley cells, polar zones, and Coriolis Effect
- Forms on convection currents -
Earth’s tilt and seasons
Ocean Currents
Rain Shadows