Transcript Winds of the World

Winds of the World
Global and Local Winds
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Global Winds
Global winds are a part of air circulation that
moves across the Earth.
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They are formed from the uneven heating of
the Earth and the resulting pressure
differences.
Polar Easterlies
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Location: found from the poles down to 60
degrees latitude in N & S hemispheres
Facts:
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Formed from cold, sinking air moving down from
the poles
Responsible for the cold weather in the US
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Westerlies
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Location: between 30 & 60 degrees latitude,
in both N & S hemispheres
Facts:
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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
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Trade winds
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Location: 30 degrees to the equator in both
hemispheres
Facts:
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Coriolis effect causes the trades to curve
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Curve to west in NH
Curve to east in SH
Early traders used the TW to sail from Europe to
America
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The Doldrums
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Location: 0 degrees latitude; @ equator
Facts:
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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)
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The Horse Latitudes
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Location: @ 30 degrees latitude in both
hemispheres
Facts:
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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
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Jet Streams
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Location: upper troposphere & lower
stratosphere
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Facts:
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Narrow belts of winds
Do not follow regular paths
Can reach speeds of 400km/h
Affect the movement of storms & planes
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Local Winds:
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Types:
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Land Breezes
Sea Breezes
Mountain Breezes
Valley Breezes
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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
Sea Breeze
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Location: air moves from the sea to the
land
Facts: (During the day)
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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.
Land Breeze
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Location: air moves from the land to the sea
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Facts: (During the night)
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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.
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Mountain Breeze
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Location: cool air sinks from the mountain
top into the valley below
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Facts:
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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.
Animation of mountain breezes
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Valley Breeze
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Location: warm air moves up the mountain
from the valley below
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Facts:
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The sun heats the valley floor & warms the air
above it.
The warm air rises creating a valley breeze.
Animation of valley breeze
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Higher Order Thinking Skills
Questions (HOTS)
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How are areas of high and low pressure created?
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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?
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Why doesn’t the wind flow in one huge belt from the poles to
the equator?
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Why doesn’t wind blow directly north or south?