2Wind is the movement of air caused by differences in air pressure Review of AirAir MovementWind is the movement of air caused by differences in air pressureThe greater the difference, the faster the wind movesAir PressureDifferences in air pressure are caused by the uneven heating of EarthAir travels in many large circular patterns called convection cells.Uneven heating produces pressure belts which occur every 30° latitude
3Pressure BeltsAs warm air rises at the equator and moves toward the poles, it coolsAs it cools, some of the air sinks around 30° north and south of the equator causing high pressure beltsAt the poles, cold air sinks and moves towards the equatorAround 60° north and south, the air begins to heat up and rise creating low pressure belts.
4Coriolis EffectWinds do not travel north or south, because earth rotating.The curving of the path of winds and ocean currents dues to earth’s rotation is the"Coriolis Effect"In the northern hemisphere, winds traveling north curve east.In the southern hemisphere, winds traveling south curve west
5Jet StreamThe jet streams are narrow belts of high speed winds that blow in the upper troposphere and lower stratosphereSeparates warm air from cold airThe term "jet stream" is often used to refer to the rivers of wind high in the atmosphere - above about 20,000 feet - that steer storms. They also help determine locations of areas of high and low air pressure at the Earth's surface.
6Global WindsThe combination of pressure belts and the Coriolis Effect cause GLOBAL WINDSSome examples of global winds are polar easterlies, westerlies, and trade windsRemember!Northern Hemisphere deflects east (right).Southern hemisphere defects west (left).
7Global Winds - Polar Easterlies Wind belts that extend from the poles to 60° latitudeFormed from cold sinking air moving from the poles creating cold temperatures
8Global Winds - Westerlies Wind belts found between 30° and 60° latitudeFlow towards the poles from west to east carrying moist air over the United States
9Global Winds - Trade Winds Winds that blow from 30° almost to the equatorCalled the trade winds because of their use by early sailors
10Global Winds - Doldrums Located along the equator where no winds blow because the warm rising air creates an area of low pressure
11Global Winds - Horse Latitudes Occur at about 30° north and south of the equator where the winds are very weakMost deserts on the Earth are located here because of the dry air
13Generally move short distances and can blow in any direction Local WindsGenerally move short distances and can blow in any directionCaused by geographic features that produce temperature differences
14Local Winds - Sea Breezes High pressure is created over the ocean during the day and low pressure over land due to uneven heatingAir moves from the ocean to the land creating a sea breezeSee a satellite animation at
15Local Winds - Land Breezes Low pressure occurs over the ocean during the night and high pressure over land due to the uneven heating of earthThis causes wind to move from the land to the ocean creating a land breeze
16Local Winds - Animation Go to and view the animation of land breeze and sea breeze.Sketch the a land breeze and a sea breeze in your notes.