| Terms |
Definitions |
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Thermally Direct Cell
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warm air rises and cold air sinks
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Ekman Spiral
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surface winds drive surface currents, and each layer of water drags the layer below, but the Coriolis Force changes each layer's direction slightly to make a spiral effect
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The Hadley Cell
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a cellular circulation of air in which warm air rises and cold air sinks, so that cold air from the poles moves to the equators at the surface, then rises as it warms and goes back to the poles aloft
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Converging surface flows cause
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low surface pressure, uprising air, heavy precipitation
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Ferrel Cell
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In the three-cell model, 30 degrees to 60 degrees latitude, thermally indirect cell in subpolar low
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In the three-cell model, the Hadley cell goes from.... to.....
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0 degrees to 30 degrees latitude
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Newton's Third Law
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For every action there is an equal and opposite reaction
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Polar Cell
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In three-cell model, 60-90 degrees latitude, Hadley-type thermally-direct cell in polar high
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Jet streams
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swiftly flowing air currents aloft
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Intertropical Convergence Zone (ITCZ)
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at equator, NE trades meet SE trades and converge, rise, and turns back into Hadley cell
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Wind and pressure systems aloft
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Winds aloft are stronger due to low friction, it is close to a geostrophic system and three-cell model doesn't apply
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Diverging surface flows cause
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high surface pressure, sinking air, dry climate
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Trade Winds
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wind from horse latitudes goes back to the equator, but is directed west by the Coriolis Force, causing Northeasterly winds
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Seasonal highs and lows
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(over continents) Winter: Siberian, Canadian highs; Summer (thermal lows): SE US, Iran
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Tropopause Jet Streams
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Subtropical; Polar- as a result of strong temperature gradients, there are strong westward winds and a meandering pattern that may merge or split, discontinuous
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Semi-permanent highs and lows
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persist throughout the year, correspond to converging/diverging upper air masses (over ocean) (Bermuda, Pacific highs / Icelandic, Aleutian laws)
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General Circulation
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prevailing winds on a global scale
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Thermally indirect cell
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cold air rises and warm air sinks
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Horse latitudes
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weak horizontal winds due to small Pressure Gradient in subtropical highs
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Subtropical Highs
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at equator, high surface pressure resulting from air convergence, cool air sinks and warms to cause clear skies and major deserts
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Newton's Third Law applied to the atmosphere
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The atmosphere exerts a friction on the Earth's surface driving surface currents of the ocean
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Is the Single Cell model accurate?
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No, because it is too simple.
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The Single Cell model of general circulation
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a simplified model that assumes that the earth's surface is uniformly covered in water, no seasonal variations, earth does not rotate
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The general circulation of the atmosphere is the result of...
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uneven heating of the earth's surface and the earth's rotation so that the air circulates in order to balance heat and pressure distribution.
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The Three Cell Model of general circulation
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a simplified model that assumes that the earth is covered entirely in water, there are no seasonal variations, and the earth rotates
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gyres
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circular whirls of ocean currents
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Water Upwelling
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wind along the coast forces warm surface water away from coast so deeper cold water rises to replace it
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