Atmospheric Circulation And More Essay, Research Paper

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 largest wind belt. The westerlies, they lie between 35 and 60 degrees

north and south latitude. The wind blows from the west , thus their name.

The westerlies are in the Ferrell cell. Cold air from the polar regions

falls down and then is heated up and pushed upward with the westerlies.

>From 65 to 90 degrees north and south lie the polar easterlies. It exists

because of the pressure gradient that is created by the temperatures. The

winds are also deflected by the coralias effect. This deflection air is

to the right in the northern hemisphere, and to the left in the southern

hemisphere. The reason that this happens is because of the rotation of

the earth on its axis.

Two moving patterns of the general circulation of the atmosphere

are the cyclones and anticyclones. Cyclones are low pressure systems

characterized by converging and rising air. On the other hand

anticyclones are characterized by high pressure because they have

diverging air that is descending. There are also land and sea breezes

which are produced by daily differences in cooling and heating of the land

and water. Sea breezes bring cooler air in the day, while land breezes

push cooler air over the water at nighttime.

There also exists radiation surpluses and deficits through out the

earth. There is a constant surplus between the latitudes of 15 degrees

north and 15 degrees south. In the latitudes between 15 and 38 degrees

north and south there is a net radiation surplus that varies annually.

There is a net radiation deficit annually in the latitudes from 38 to 90

degrees north and south. These surpluses and deficits are due to the high

sun angle in the low latitudes, as well as the increased length of

daytime.

Finally the seasons of the earth are determined by the tilt of the

earth on its axis. The earth is on a tilt of 23.5 degrees. When it

revolves around the sun the earth is exposed to the sun at different

degrees at different months of the year. Because of this phenomenon we

get seasons on the earth. The earth and all of its circulation patterns,

energy balances, and motions of the atmosphere are all very complex;

however, it can be easily understood by my wonderful summary.