Title: Atmosphere in Motion; Wind Bands Page #: 75 Date: 2/25/2013 Table of Contents Title: Atmosphere in Motion; Wind Bands Page #: 75 Date: 2/25/2013

Objective Students will be able to explain the origin of Earth’s prevailing wind patterns.

Essential Question Where do Earth’s prevailing wind patterns come from?

Word of the Day Wind: The process by which heat is distributed from Earth’s equator to the poles.

Why does Jupiter have stripes? What do the arrows Indicate?

Wind Bands Winds are the product of warm air rising at the equator and moving towards the poles. Coriolis Effect (a result of Earth’s rotation) causes air to be deflected to The right in the Northern Hemisphere The left in the Southern Hemisphere

Wind Bands Wind Bands (“Prevailing Winds”): Earth’s major wind patterns. Direction of wind is determined by 3 factors: Convection Currents Earth’s rotation from West to East Air pressure (High = Cold; Low = Warm)

Wind Bands 3 Factors of wind direction create 3 convection cells in each hemisphere. These convection cells are mirror images of each other.

Wind Bands Convection cells are defined by latitude: Northern Hemisphere 0º - 30ºN “Northeast Trade Winds,” wind blows from Northeast 30º - 60ºN “Westerlies,” wind blows from West 60º - 90ºN “Polar easterlies” wind blows from East

Wind Bands Convection cells are defined by latitude: Southern Hemisphere 0º - 30ºS “Southeast Trade Winds,” wind blows from Southeast 30º - 60ºS “Westerlies,” wind blows from West 60º - 90ºS “Polar easterlies” wind blows from East

Wind Bands Spots of low wind: Equator - “Doldrums” air is rising vertically. 30ºN and 30ºS - “Horse Latitudes” air is descending vertically.