Winds of the World Global and Local Winds Used with permission of V. Morris, Phillips Preparatory School

Global Winds Global winds are a part of air circulation that moves across the Earth. They are formed from the uneven heating of the Earth and the resulting pressure differences. Used with permission of V. Morris, Phillips Preparatory School

Used with permission of V. Morris, Phillips Preparatory School Polar Easterlies Location: found from the poles down to 60 degrees latitude in N & S hemispheres Facts: Formed from cold, sinking air moving down from the poles Responsible for the cold weather in the US Used with permission of V. Morris, Phillips Preparatory School

Used with permission of V. Morris, Phillips Preparatory School

Used with permission of V. Morris, Phillips Preparatory School Westerlies Location: between 30 & 60 degrees latitude, in both N & S hemispheres Facts: Flow toward the poles from west to east Can carry moist air over the US, producing rain & snow Helped settlers return to Europe Influences your weather Used with permission of V. Morris, Phillips Preparatory School

Used with permission of V. Morris, Phillips Preparatory School

Used with permission of V. Morris, Phillips Preparatory School Trade winds Location: 30 degrees to the equator in both hemispheres Facts: Coriolis effect causes the trades to curve Curve to west in NH Curve to east in SH Early traders used the TW to sail from Europe to America Used with permission of V. Morris, Phillips Preparatory School

Used with permission of V. Morris, Phillips Preparatory School

Used with permission of V. Morris, Phillips Preparatory School The Doldrums Location: 0 degrees latitude; @ equator Facts: Means dull or sluggish Form where trade winds meet Very little wind because the warm, rising air @ the equator creates an area of low pressure (remember air moves from high to low pressure, so there is NO wind if there is no high pressure) Used with permission of V. Morris, Phillips Preparatory School

Used with permission of V. Morris, Phillips Preparatory School

Used with permission of V. Morris, Phillips Preparatory School The Horse Latitudes Location: @ 30 degrees latitude in both hemispheres Facts: Sinking air creates an area of high pressure, creating weak winds Legend says the horse latitudes got their name because the weak winds stranded horse-trading ships coming from Europe to America To survive the sailors on the ships threw the horses overboard to save food and water Used with permission of V. Morris, Phillips Preparatory School

Used with permission of V. Morris, Phillips Preparatory School

Used with permission of V. Morris, Phillips Preparatory School Jet Streams Location: the upper & lower atmosphere (upper troposphere & lower stratosphere) Facts: Narrow belts of winds Do not follow regular paths Can reach speeds of 400km/h Affect the movement of storms & planes Used with permission of V. Morris, Phillips Preparatory School

Used with permission of V. Morris, Phillips Preparatory School

Used with permission of V. Morris, Phillips Preparatory School Local Winds: Types: Land Breezes Sea Breezes Mountain Breezes Valley Breezes Local winds can move from any direction but only move short distances. They are formed from the uneven heating of the Earth and pressure differences Used with permission of V. Morris, Phillips Preparatory School

Used with permission of V. Morris, Phillips Preparatory School Sea Breeze Location: air moves from the sea to the land Facts: (During the day) Air over water is cooler & creates high pressure. Cool, dense air moves toward land, creating a sea breeze. Air over land is warmer, so the warm air rises, creating low pressure over land. Used with permission of V. Morris, Phillips Preparatory School

Used with permission of V. Morris, Phillips Preparatory School Land Breeze Location: air moves from the land to the sea Facts: (During the night) Air over land is cooler & creates high pressure. Cool air moves toward the sea, creating a land breeze. Air over the sea is warmer, so it rises creating low pressure. Used with permission of V. Morris, Phillips Preparatory School

Used with permission of V. Morris, Phillips Preparatory School

Used with permission of V. Morris, Phillips Preparatory School Mountain Breeze Location: cool air sinks from the mountain top into the valley below Facts: Mountain tops cool faster than valleys at night. Cold air is dense (heavier) so it sinks from the mountain tops into the valleys below creating a mountain breeze. Used with permission of V. Morris, Phillips Preparatory School

Animation of mountain breezes Used with permission of V. Morris, Phillips Preparatory School

Used with permission of V. Morris, Phillips Preparatory School Valley Breeze Location: warm air moves up the mountain from the valley below Facts: The sun heats the valley floor & warms the air above it. The warm air rises creating a valley breeze. Used with permission of V. Morris, Phillips Preparatory School

Animation of valley breeze Used with permission of V. Morris, Phillips Preparatory School

Higher Order Thinking Skills Questions (HOTS) How are areas of high and low pressure created? Knowing that air moves from areas of high pressure to areas of low pressure, which direction should the winds of the Earth move—in what direction from where? Why doesn’t the wind flow in one huge belt from the poles to the equator? Why doesn’t wind blow directly north or south? Warm air rises creating areas of low pressure and cold air sinks creating areas of high pressure. Pressure depends on the density of the molecules; remember cold air is denser than warm air. Warm air rises creating areas of low pressure and cold air sinks creating areas of high pressure. Pressure depends on the density of the molecules; remember cold air is denser than warm air. Air moves from areas of high pressure to areas to low pressure, so wind generally moves from the poles to the equator. Warm air cools and sinks; cools and sinks, every 30 degrees creating pressure belts from pole to equator to pole. Used with permission of V. Morris, Phillips Preparatory School