Global Patterns Of Air Circulation Essay

Student Name: Shane Eristhee

Student Identification Number: AC1109024

Course Number and Title: SC260 Introduction to Ecology

Assignment Number and Title: Assignment 4

Date of Submission:

Atmospheric circulation is the largest scale movement of air and together with ocean circulation is the means by which thermal energy is redistributed on the surface of the earth. It can be viewed as a heat engine driven by the sun’s energy. The atmosphere transports heat throughout the globe extremely well but present day atmospheric characteristics prevent heat from being carried directly from the equator to the poles.

Global patterns of atmospheric heating and circulation are centers around a three wind cells model, they are the Hedley cell, the Ferrel

It beings with warm air rising at the equator and sinking at about 30 degrees latitude. The Ferrel cell is the average motion of air in the mid latitude. It is characterised by the sinking air near 30 degrees and rising air farther poleward. The Ferrel cell is complicated because it has warm air rising at higher latitudes near the Polar cell and cooling as it moves to the lower latitudes near the Hadley cell. The polar cell is the smallest and weakest cells among the three. It extends from between 60 and 70 degrees north and south of the poles. In these cells air sinks over the highest latitudes and flows out towards the lower latitudes at the surface.

High precipitation in the tropics is caused by the warm air from the hemispheres converging in the Inter Convergence Zone(ICZ) and the rise of this air is caused by low pressure and causes convection in the atmosphere.

In the tropics, high precipitation occurs as a result of warm prevailing winds being obstructed by mountain ranges, since the mountains force the moisture in those winds to sink on the side of the mountain that is blocking the winds, leaving the other side with low