Transcript C. 22 Section 3 Atmospheric Circulation

C. 22 Section 3
Atmospheric Circulation
Air near Earth’s surface
generally flows from the
poles toward the equator.
Coriolis Effect
 This
affects the circulation of the
atmosphere as well as the oceans.
 When air moves toward the pole, it
travels east faster than the land
beneath it does—this equals a curved
path.
 Remember that the rotation of the
Earth is what is causing the curve.
Winds blowing from high pressure to lower
pressure areas curve due to Coriolis effect
also.
Objects are deflected to the right in the
Northern Hemisphere and are deflected to
the left in the Southern Hemisphere.
 The faster an object travels, the greater
the Coriolis effect.

Global Winds
 Winds
that blow in one main
direction are called prevailing
winds.
 Trade Winds are those that flow
toward the equator between 30-0
degrees latitude. They are named
from the direction they flow i.e.
from the north = north trade winds.
What are the Westerlies?
The winds between 30-60 degrees latitude
that are flowing toward the poles but
deflected by the Coriolis effect.
 The westerlies blow thoughout the U.S.
 Polar Easterlies are surface winds of
high pressure by the 60 degree latitude
pole area that are deflected by the
Coriiolis effect and become the easterlies

Here are the wind patterns:
Doldrums
 This
is a narrow zone where the
trade wind systems of the north and
south hemispheres meet at the
equator.
Horse Latitudes
 Warm
moist air heads upward and
surface winds are weak and variable.
Then the air approaches 30 degrees
latitude, it comes down and a highpressure zone forms.
Wind and Pressure Shifts
 When
the sun’s ray shift north or
south as seasons change, so can the
winds and pressure areas.
 Jet streams-these are narrow bands
of high-speed wind that blow in the
upper troposphere and lower
stratosphere.
 Some are polar jet streams and also
subtropical jet streams.
Polar jet stream
Subtropical jet stream
Local Winds
 These
are not part of the global wind
belts.
 The local conditions and
temperatures are what influence
local winds.
 Breezes are gentle winds that extend
over distances of less than 100 km.
Land and Sea Breezes

As the sun heats the land the warmed air rises
and the cool air from the water area moves in to
replace the warm water. This is a sea breeze
because the air is moving from the sea into the
land.
 So
what is a land breeze?
Land breeze:
 During
the night the land cools more
rapidly than the water and a land
breeze flows from the cool land
toward the warmer water.
Mountain and Valley Breeze
 Same
thing—during the day a gentle
breeze blows upslope because the air
has been heated in the valley. This is
the valley breeze.
 At night, the mountains cool more
quickly than the valley and a
mountain breeze descends down
the mountain (Remember cold air is
more dense and sinks).
OKAY!!
 Chapter
22 is complete!