Roberta A. Mazzucco
The intense heat of the Sun determines the Earth's weather. About one third of all the light waves that reach the Earth are reflected back into space. The remaining two thirds are absorbed by the Earth. The sunlight passes through the atmosphere and heats the ground which in turn warms the air near the surface. The atmosphere keeps the warmth from escaping. This is what is termed the greenhouse effect. Like the windows in a greenhouse the atmosphere traps the heat inside. The balance of temperature is very important to life on our planet. If the temperature drops a few degrees everything would begin to freeze and another ice age could occur. If the temperature rose a few degrees the polar caps might begin to melt.
The difference in climate around the Earth is caused by the fact that the Sun does not heat the Earth evenly. The equator is where the rays of the Sun hit most directly. As you move north or south toward the poles the Sun's rays slant.
The unequal heating sets up air masses that move around the Earth. The colder masses become heavy and move downward while the warmer massed become lighter and rise. The air from the poles moves toward the equator and the equatorial air masses move northward. This continuing movement is the basis for the weather patterns that occur on the Earth.
The Earth is spinning from west to east at about a thousand miles per hour at the equator but slower at the poles.(18) The difference in speeds make the winds and ocean currents curve to their right in the Northern Hemisphere and to the left in the
As the earth spins the irregular surface of the earth and the different amounts of water in the air cause many complex and unusual wind patterns. As the Sun shines on the Earth heat is absorbed at different rates. The trees and forests absorb most of the light rays that fall on them. However, the mountains and areas covered with snow reflect as much as nine tenths of the Sun's rays back. They remain snow covered throughout the seasons. Water warms and cools more slowly than the land. The oceans and other large bodies of water store heat from sunlight and release it slowly at night even during the winter. Land areas can't store as much heat as water. For this reason areas like the Midwest have rougher winters and warmer summers compared to areas along the coastline.