Wind:
What makes it blow?
Wind is the movement of air from a region of high pressure to a region of
lower pressure. These areas of high and low pressure are created from temperature differences caused by the sun heating the earth, which in turn heats the
atmosphere.

Pressure gradient force:

Air moves from high to low pressure areas

-so-

The lower the pressure area the stronger the wind.

Coriolis Effect:

The force due to the Earth's rotation that cause objects in motion to veer to the right in the Northern Hemisphere and to the left in the Southern Hemisphere.

Hypothetical look of
planetary wind on planet if:

  1. All the surface was water.
  2. No rotation of the planet. Which would mean no carioles effect.

Source: website of the National Weather Service,
Southern Regional Headquarters - US

Air Movement (AKA wind) on planet Earth:


Image in its original context on the page: www.geology.wmich.edu/ kominz/otln8.htm

Global Wind Patterns:
Winds named for the direction they come from

"Special" surface wind zones
Doldrums - an area of low pressure occurring where the trade winds meet along the equator. Winds here are usually calm or very light and so ships would avoid the area because they would only be pushed along very slowly.
ITCZ - The easterly trade winds of both hemispheres meet at an area near the equator called the "Intertropical Convergence Zone (ITCZ)
Horse Latitudes - These are located mostly over the oceans, at about 30° latitude in both of the hemispheres. Stories say that sailors gave the region of the subtropical high the name "horse latitudes" because ships relying on wind power stalled; fearful of running out of food and water, sailors threw their horses and cattle overboard to save on provisions.
Surface wind bands on Earth
Trade Winds - These are found from 0-30 degrees latitude (aka Tropical Easterlies)
Prevailing Westerlies - These are found from the 30-60 degrees latitude (aka Westerlies).
Polar Easterlies - These are found from the 60-90 degrees latitude.
Different Kinds of Wind Across the Surface:
Sea (large open water) Breeze onto Land:
A sea-breeze (or onshore breeze) is a wind from the sea that develops over land. It is formed by increasing temperature differences between the land and water which create a pressure low over the land due to its relative warmth and forces higher pressure, cooler air from the sea to blow onto the land. Source: http://en.wikipedia.org/wiki/Sea_breeze
Land Breeze from sea or a Lake
At night, the land cools off quicker than the open water, which forces the dying of the daytime sea breeze. If the land cools below that of the adjacent open water, the pressure over the water will be lower than that of the land. This creates a land breeze flowing back out towards the open water.
Source: http://en.wikipedia.org/wiki/Sea_breeze#Land_Breeze
Valley Breeze: (occurs mainly in afternoons)
A wind formed during the day by the heating of the valley floor. As the ground becomes warmer than the surrounding atmosphere, the lower levels of air heat and rise, flowing up the mountainsides. As the warm air rises and cools over the mountains clouds may form from the warm moist air condensing. This is known as a ANABANTIC wind.
Mountain Breeze: (occurs evenings and night)
This wind is formed at night by the radiational cooling along mountainsides. As the slopes become colder than the surrounding atmosphere, the air closest to the mountainside cools and drains down into the valley. This wind is known as a KATABATIC Wind.
Source: http://www.weather.com/glossary/m.html#mtnbrz

ANABATIC WIND -
A wind that is created by air flowing uphill.
KATABATIC WIND -
A wind that is created by air flowing downhill. This is also known as a Chinook wind.

Chinook Wind
A Chinook is produced by a downsloping wind. As air downslopes it warms adiabatically and decreases in relative humidity. The Chinook is common in the northern plains of the United States in winter.
Source: http://www.theweatherprediction.com/wind/

“In popular myth, Chinook is supposed to mean "snow eater", as a strong Chinook can make a foot of snow all but vanish inside of one day. The snow partially melts, and partially evaporates in the dry wind. However, the true origin of the name is that "Chinook Wind" in the local language of the fur traders meant that the wind came from the direction of the country of the Chinooks (the lower Columbia River, i.e. from across the Rocky Mountains).” Source http://en.wikipedia.org/wiki/Chinook_wind

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To High Low Pressure Atmospheric Fronts - Page 3

To Fog: What causes fog and types of fog - Page 5

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