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Atmospheric Science

Submitted by mpetracchi on Tue, 09/10/2019 - 16:42

The study of the climate, specifically winds and precipitation, has helped me understand more about the earth and why it is we experience what we do. It all begins with the sun’s solar radiation reaching the earth. Between 30 degrees North and South, known as the tropics, is where the sun’s solar radiation hits its most direct. It varies due to the tilt of the earth, with the equator in the dead center. At the equator, the rays heat the surface and produce pockets of warm air, which rise due to a lower density than the cool air around it. This rise in warm air creates a low-pressure zone. As the air pocket increases in altitude, its heat is transferred to the surrounding air and the carrying capacity of water in the previously warm air decreases. This causes the formation of water droplets and clouds. For this reason, the equator experiences a lot of precipitation. Once the air has cooled it is carried north and south from the equator until 30 degrees North and South where it cools and falls. This process is known as subsidence. At these latitudes, there is high pressure and therefore no clouds or precipitation. This specific rotation of air near the equator is known as a Hadley cell. There are two more cells known as Ferrell, and Polar cells. Ferrell cells are an intermediate between Hadley and Polar cells and occur between 30 and 60 degrees. Above that is where the polar cell exists. These wind patterns help us determine what are known as prevailing winds; winds that are observed consistently and can be used to make predictions on the climate at any given location.  When looking at a map of the earth, these winds always point towards either 0 or 60 degrees latitude and away from 30 and 90 degrees latitude. This is because at 30 and 90 degrees there are pockets of high atmospheric pressure generated by the subsidence effect, and fluids tend to flow from high to low pressure, therefore away from 30 and 90 degrees.