Atmospheric Circulation

3 Pages 702 Words

The global energy balance and atmospheric motion mainly determine
the circulation of the earth's atmosphere. There is a hierarchy of motion
in atmospheric circulation. Each control can be broken down into smaller
controlling factors. The global energy balance is an equal balance of
short-wave radiation coming into the atmosphere and long-wave radiation
going out of the atmosphere. This is called thermal equilibrium. The
earth is at thermal equilibrium; however, there can have a surplus or
deficit of energy in parts of the heat budget. If you have a net
radiation surplus warm air will rise, and a net radiation deficit will
make the air cool an fall. Air gets heated at the equator because of the
inter tropical convergence zone and rises to the poles. There the air is
cooled and it floats back down to the equator where the process is
repeated. Another major contributing factor to the circulation of the air
is due to the subtropical highs. These highs like the ITCZ migrate during
the different seasons.
The idealized belt model is a great representation of the general
circulation of the atmosphere. The equatorial belt of variable winds and
calms ranges from 5 degrees north to 5 degrees south. This wind belt is
characterized by weak winds and low pressure from the inter tropical
convergence zone. As you go further north or south you encounter the
Hadley Cells. Hadley cell circulation is caused by the movement of high
pressure from the latitudes at 5 to 30 degrees north and 5 to 30 degrees
south to low pressure areas around the equator.
The movement of air from high pressure to low pressure causes
convergence. This convergence generates the production of wind. The
winds that are produced from this are the trade winds. The winds blow
from a northwest direction in the northern hemisphere, and in the southern
hemisphere the winds blow from a southeast direction. The trade winds are
the large...