The Atmosphere: Part 7: The Extratropical Circulation

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The AtmospherePart 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
net
ocean
atmosphere
Trenberth Caron (2001)
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Circulation in our 2D model
O
f gt 0
f 0
f lt 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
cold water bath
hot water bath
working fluid
rotating turntable
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Rapid rotation baroclinic instability
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Atmospheric heat transport
extratropics eddy transport
tropics direct overturning
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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
net
ocean
atmosphere
Trenberth Caron (2001)
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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