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Describe and account for the nature of global atmospheric circulation.
Global atmospheric surface pressure is the movement of air on a large scale and the means by
which solar energy is distribution on the earth's surface.
The global heat budget is the balance between incoming and outgoing solar radiation. Incoming
solar energy varies at different times of the year and for different locations across the globe.
However, the sun heats the Earth's surface unevenly due to variations in latitude. The tropics have
an energy surplus as they gain more from isolation than is lost by radiation. But the high latitudes
and polar latitudes have an energy deficiency losing more radiation than is gained by insolation.
This imbalance sets up a transfer of heat energy from the tropics to higher latitudes.
The movement of air at ground level is heated and the warm air becomes less dense and rises.
Rising air creates low pressure at the equator, as air moves away from the surface. Air cools as it
rises, creating high rainfall. As the air mass cools in the upper atmosphere, it becomes heavier and
sinks back to the Earth's surface creating high pressure. This creates a cell, or circular motion of
The Singular convection model helps us imagine the Earth as a nonrotating sphere and that the
differences in air temperature at the equator and the Poles creates differences in air pressure e.g.
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Air always moves from high pressure to low pressure allowing heat to be moved around the globe.
A convection cell forms in both hemispheres as a result.
However, since the earth rotates, the axis is tilted, and there is more land mass in the northern
hemisphere than in the southern hemisphere. This creates zones of high and low pressure which
can be explained through the use of the tricellular model of atmospheric circulation.…read more
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Northern Hemisphere and the left in the Southern
At the Equator the Earth has a greater circumference than towards the Poles. As a result, the air
has to travel faster here as the Earth rotates. In response to the greater distance, the air moves
towards the Poles at an angle to catch up with the slower moving air further North or South.…read more