The Global System's Effect on Climates

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The Global System's Effect on Climates

The global pattern of climate is affected by:

* latitude

* land and sea

* relief

* ocean currents

Latitude

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The Equator receives greater amounts of solar heating than latitudes

further north or south. Places therefore nearer the Equator are much

warmer than those closer to the Poles. Nearer the Poles precipitation

will be more variable with lower temperatures. More will fall as snow,

covering the ground for long periods in winter.

The amount of solar energy received by each hemisphere varies because

of the tilt of the Earth and its orbit around the sun. This gives

summer and winter seasons. Places nearer the Poles have greater

differences between summer and winter in temperature and

precipitation.

At the Equator air, warmed from below, becomes less dense and is

forced to rise as strong convection currents, creating low pressure at

the surface (ITCZ). Convectional currents of warm, moist air cool to

give heavy, daily thunderstorms

Strong, steady winds converge to fill the low pressure from the north

and south, but the spinning of the Earth diverts the winds slightly to

the right in the northern hemisphere and they become the north-east

Trade Winds. In the southern hemisphere winds are diverted to the

left, producing the south-west Trade Winds.

Air in the upper atmosphere flows away from the Equator and cools.

Cooling air becomes denser, heavier and descends back to the surface

on the polar sides of the 'Cell', causing zones of high pressure at

about 30° north and south of the Equator (sub-tropical high pressure

zone). Descending a...

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...han those in Central Europe.

Prevailing winds from the south west, passing over the ocean current

are warmed and pick up large amounts of moisture. The precipitation,

caused when the air is forced to rise over mountains or at fronts,

provides the British Isles with a reliable precipitation all year.

Cold ocean currents from colder polar waters have a contrasting

effect. Those flowing south along coasts in the northern hemisphere

keep summer temperatures cooler and the air drier than normal for that

latitude. Coastal fogs occur when warmer air from over the land is

cooled by the cold water.

In tropical areas warm ocean currents, such as the Kuro Siwo which

flows north towards Japan, are the source of the large amounts of

energy and moisture that can result in the development of intense

depressions or typhoons.

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