Download Much of the sun`s energy is absorbed by the Earth`s surface

Much of the sun’s energy is absorbed by the Earth’s surface. Land absorbs the sun’s
energy more quickly and heats up faster than bodies of water. Land also releases heat and
cools off faster when the sun goes down than bodies of water do. Because the Earth’s
surface is heated unevenly, the air above is in constant motion. Cold air is heavier than
warm air, so it sinks, forcing the lighter warm air to rise. The air moving upward in the
atmosphere causes what is called updrafts. Have you ever seen a birds soaring on
updrafts?
On the surface, two different places can have different temperatures; therefore have
differences in air pressure. The differences in air pressure cause air to move from the area
of higher pressure to the area of lower pressure. This movement of air is called wind.
Winds can be local, affecting a small area, or global, affecting a large area. Local winds
depend on local changes in temperature. The seashore is a good example of local winds.
During the day, the land heats up more quickly than the water, so breezes blow from the
sea to the land. At night, air over the water is warmer than the air over the land, which
causes breezes to blow from the land to the sea.
Prevailing winds are global winds that blow constantly from the same direction. These
winds are caused by the uneven heating of large parts of Earth’s atmosphere and by
Earth’s rotation. The warmth of the equator and the coldness of the north and south poles
causes a constant flow of air. The rotation of the Earth causes these winds to curve. In
most of the United State, the prevailing winds curve to the east, producing west winds, or
westerlies. These prevailing westerlies cause most of the weather systems in the United
States to move from west to east. This helps forecasters with their weather predictions.
What happens in Kansas today will probably happen here in Virginia tomorrow!
Weather is also affected by the air masses that surround the Earth and move in patterns.
An air mass is a large body of air which has about the same temperature and humidity
throughout. Some air masses are colder, and some are warmer. When these air masses
meet and form a boundary, it is called a front. The front is named by the air front that is
moving in. A cold front forms when a cold air mass moves into an area occupied by a
warmer air mass. This normally produces thunderstorms. A warm front forms when a
warm air mass moves into an area occupied by a colder air mass. When this happens, we
might have gentle rain storms. Blue connected arrows are used to show a cold front. Red
connected bumps show a warm front.