What Causes the Wind Worksheet

Definitions Sea breeze: Cool breeze that blows off the water during the day Land breeze: Breeze that blows at night from the land to the sea

Isobar: Line on a weather map connecting places with the same atmospheric pressure Coriolis Effect: Apparent curvature of the winds, ocean currents or objects moving long distances along Earth’s surface; caused by Earth’s rotation

Jet Stream: Currents or very fast winds that flow in the upper atmosphere; separate hot from warm from cold

Anemometer: A device that measures wind speed

Pressure gradient: Rate of change in air pressure between two points on a map   Planetary Wind Belts (ESRT 14): Latitude zone of prevailing wind conditions caused by uneven heating of Earth and Earth’s rotation Prevailing winds: Wind that blows more often from one direction than from any other

Key Concepts What causes the wind? The wind is caused by heat flow by way of convection within the atmosphere What do winds result from? Winds result from the uneven heating of Earth’s surface, which causes a difference in air pressure Cool places usually have relatively high-pressure air pressure and warmer places have relatively lower pressure air pressure

****KEY IDEA**** Winds always blow from areas of high pressure to areas of low pressure

Winds always blow fastest where the isobar lines are closest together The wind direction is influenced by Earth’s rotation   During the day, land heats up more quickly than water Warm air rising over land causes low pressure, a sea breeze and clouds over the land. This happens during the day. Warm above slowly cooling water at night creates low pressure, a land breeze and clouds over the water. This happens at night.

If the Earth were not spinning, the pattern of wind circulation would be relatively simple. Without rotation, winds would blow straight from areas of high pressure (North Pole) to areas of low pressure (equator)   In the Northern Hemisphere, winds blowing out of a high pressure area curve clockwise

The winds blowing into a low-pressure area turn counterclockwise. Winds that converge into a low at the surface and rise into the atmosphere must result in winds that  diverge aloft (above).   Low pressure systems are also called cyclones High pressure systems are also called anti-cyclones

Jet streams blow from west to east in mid-latitudes where cold air meets warmer air   Why are jet streams important?   Jet streams are important because they influence the development and movement of storm systems Like winds, ocean currents generally move in the same direction

*****KEY CONCEPT***** Winds are named by the direction from which they come Example: A north wind in NYS usually brings cold air because it comes from the Canada/the north.

Prevailing Winds Difference in air pressure and prevailing winds can often mean different weather conditions Example: In the winter, the northern portions of the US often get cold weather conditions from Canada caused by northerly prevailing winds. In the summer, the same regions usually have more southerly prevailing winds

Monsoons: A regular and extreme weather change caused by the shift of wind and pressure belts, which is directly related to the changes in seasons Example: India- when winds are off the land, India experiences a drought. When winds are off the water, India experiences high amounts of rain

Much of the contiguous US is affected by planetary winds that blow from the southwest to the northeast As a result, weather changes in the US generally move from a southwesterly direction to a northeasterly direction

Surface ocean currents are caused by wind blowing over the oceans and transferring energy to the water The directions of the surface ocean currents are also affected by blocking by landmasses and the rotation of Earth through the Coriolis effect Since ocean currents result from the transfer of energy from prevailing winds, they can seasonally shit their positions. These changes follow the motions of the vertical rays of the sun