Winds What causes winds A wind is the

Winds

What causes winds? A wind is the horizontal movement of air from an area of high pressure to an area of low pressure. n Most differences in air pressure are caused by unequal heating of the atmosphere! n Winds are caused by differences in air pressure. n High Pressure Low Pressure WIND Earth’s Surface

Wind Vane Measuring Wind n n Winds are described by their direction and speed. Wind direction is determined with a wind vane – points in the direction the wind is moving! Wind speed is measured with an anemometer. The increased cooling that a wind can cause is called the wind chill factor. Anemometer – The cups catch the wind, turning faster when the wind blows faster.

Local Winds Have you ever flown a kite at the beach on a hot summer day? Even if there is no wind inland, there may be a cool breeze blowing in from the water toward the beach. This breeze is an example of local winds! Local winds are winds that blow over short distances. n They are caused by unequal heating of Earth’s surface within a small area. n Two types of local winds are sea breezes and n

Sea Breeze (Morning) Land heats up faster than water. Hot air over land rises (Low Pressure), cool air over water falls (High Pressure). Winds move from the water (High Pressure) to the land (Low Pressure).

Land Breeze (Evening) Land cools off faster than water. Cool air over land falls (High Pressure), warm air over water rises (Low Pressure). Winds move from the land (High Pressure) to the water (Low Pressure).

Global Winds that blow steadily from specific directions are global winds. n Created by unequal heating of Earth’s surface. n Warm air rises at the equator and falls at the poles. n

Global Winds… cont… n The movement of air between the equator and the poles produces global winds. n The way that Earth’s rotation makes winds curve is called the coriolis

Global Wind Belts n The five global wind belts are the doldrums, the horse latitudes, the trade winds, the prevailing westerlies, and the polar easterlies.

Jet Streams Bands of high speed winds n Hundreds of kilometers wide, but only a few kilometers deep. n Blow from west to east at speeds of 200 -400 km/hr. n Help airplanes save fuel and time when traveling east. n

THE END! n Work on the worksheet attached to your notes! n This is your homework!