Changes in clear-sky longwave radiative cooling in the atmosphere 1979-2004
The Atmosphere: Part 7: The Extratropical Circulation
description
Transcript of The Atmosphere: Part 7: The Extratropical Circulation
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The Atmosphere:Part 7: The Extratropical Circulation
• Composition / Structure
• Radiative transfer
• Vertical and latitudinal heat transport• Atmospheric circulation• Climate modeling
Suggested further reading:
Holton, An Introduction to Dynamical Meteorology (Academic Press, 1979)
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Roles of atmosphere and ocean
Trenberth & Caron (2001)
net
ocean
atmosphere
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Circulation in our 2D model
Ω
f = 0
f > 0
f < 0
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Hadley Cell
T = Te
Plenty of APE in middle and high latitudes
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Experiment on rotating table with imposed temperature gradient
hot water bathcold water bath
working fluid
rotating turntable
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Rapid rotation — baroclinic instability
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tropics — direct overturning extratropics — eddy transport
Atmospheric heat transport
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Atmospheric heat transport
Warm air upward and poleward
Cold air downward and equatorward} Efficient poleward heat transport
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Roles of atmosphere and ocean
Trenberth & Caron (2001)
net
ocean
atmosphere
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Angular momentum budget
Low level westerlies — loss of
AM to surface through friction
Low level easterlies — gain of
AM from surface through friction
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Atmospheric angular momentum transport
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Observed angular momentum transport total
transient eddies
stationary eddies
(mean circulation)
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Eddy angular momentum transport