Download Global Wind Patterns wind belts of the general circulation The global

Global Wind Patterns
wind belts of the general circulation
The global wind pattern is also known as the "general circulation"
and the surface winds of each hemisphere are divided into three
wind belts:
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Polar Easterlies: From 60-90 degrees latitude.
Prevailing Westerlies: From 30-60 degrees latitude (aka
Westerlies).
Tropical Easterlies: From 0-30 degrees latitude (aka Trade
Winds).
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The easterly trade winds of both hemispheres converge at an
area near the equator called the "Intertropical Convergence Zone
(ITCZ)", producing a narrow band of clouds and thunderstorms
that encircle portions of the globe.
Terms for using data resources. CD-ROM available.
Credits and Acknowledgments for WW2010.
Department of Atmospheric Sciences (DAS) at
the University of Illinois at Urbana-Champaign.
Rising Air
a key process in the production of clouds and precipitation
Imagine a block of air, or air parcel, rising upward through the
atmosphere. The air parcel expands as it rises and this
expansion, or work, causes the temperature of the air parcel to
decrease.
As the parcel rises, its humidity
increases until it reaches 100%.
When this occurs, cloud
droplets begin forming as the
excess water vapor condenses
on the largest aerosol particles.
Above this point the cloud
droplets grow by condensation
in the rising air.
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If the cloud is sufficiently deep or long lived, precipitation will
develop.
The upward motions that
generate clouds and lead to
precipitation can be produced by
convection in unstable air,
convergence of air near cloud
base, lifting of air by fronts and
lifting over elevated topography
such as mountains