Atmospheric Circulation And More :: essays research papers

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.