Page 8 - Wind Waves and Weather

Petroleum Extension-The University of Texas at Austin

Wind

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he sun radiates, or gives off, energy that strikes the earth.
TMuch of this energy is in the form of light and heat. This
solar energy, however, does not affect areas of the earth equally.
Instead, the sun heats the earth’s surface unevenly. For example,
the Arctic and Antarctic receive less solar energy than the equa‑
tor. Because the earth’s axis is tilted in relation to the sun, solar
energy hits polar areas at an angle. The poles do not get as much
solar energy as the equator, where the sun’s energy strikes
head on. Therefore, it is cold at the poles and hot in the tropics.
Scientists call this temperature difference differential heating.
Another factor in differential heating is that some regions
on earth absorb more heat than others. For example, because
polar regions are covered with ice, they reflect a great deal of
heat back into the air. On the other hand, tropical areas, with
their massive amounts of dark green foliage, absorb more heat
than they reflect. Thus, the sun heats the earth unequally. Con‑
sequently, the earth heats the air in its atmosphere unequally.
The resultant mixture of warm and cool air in the atmosphere
causes wind. Wind is the horizontal movement of air in the
earth’s atmosphere.

The sun showers the earth with shortwave radiation. This short‑ Latitude and
wave radiation, or energy, is visible as light, and it provides Longitude
heat. As stated before, the angle at which the sun’s rays strike
the earth affects the amount of heat received by areas on the
earth. To understand the effect, it also helps to understand
latitude and longitude.
Geographers divide the earth into imaginary lines of lati‑
tude and longitude. Latitude is an imaginary line joining points
on the earth’s surface that are all of equal distance north or south
of the equator. Longitude is the angular distance east or west
of the prime meridian that stretches from the North Pole to the
South Pole and passes through Greenwich, England. The prime
meridian is the line of longitude that is 0 degrees (°). All other
longitudes are measured either east or west of the prime merid‑

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