The Atmosphere: Part 5: Large-scale motions

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The AtmospherePart 5 Large-scale motions

• 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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Calculated rad-con equilibrium T vs. observed T
pole-to-equator temperature contrast too big in
equilibrium state (especially in winter)
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Zonally averaged net radiation
Diurnally-averaged radiation
Observed radiative budget
Implied energy transport requires fluid motions
to effect the implied heat transport
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Roles of atmosphere and ocean
net
ocean
atmosphere
Trenberth Caron (2001)
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Basic dynamical relationships
O
Equation of motion
O
Osinf
u
f
Shallow atmosphere

z - coordinates

p - coordinates
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Basic dynamical relationships
O
Equation of motion
O
Osinf
u
f
Shallow atmosphere

z - coordinates
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Basic dynamical relationships
O
Equation of motion
O
Osinf
u
f
Shallow atmosphere

z - coordinates

p - coordinates
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Geostrophic balance
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Geostrophic balance
thermal wind shear balance
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Rotating vs. nonrotating fluids
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Rotating vs. nonrotating fluids
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Rotating vs. nonrotating fluids
O
O
f gt 0
Osinf
u
f
f 0
f lt 0
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Atmospheric energeticswhere does the energy of
atmospheric motions come from?
Flattening density/temperature surfaces
always reduces potential energy
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Atmospheric energeticswhere does the energy of
atmospheric motions come from?
Flattening density/temperature surfaces
always reduces potential energy Available
potential energy inherent in density/temperature
gradients
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Atmospheric energeticswhere does the energy of
atmospheric motions come from?
Flattening density/temperature surfaces
always reduces potential energy Available
potential energy inherent in density/temperature
gradients
In order to generate available potential
energy, on average must heat where hot and cool
where cold lt JT gt gt 0
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Atmospheric energeticswhere does the energy of
atmospheric motions come from?
Flattening density/temperature surfaces
always reduces potential energy Available
potential energy inherent in density/temperature
gradients
In order to generate available potential
energy, on average must heat where hot and cool
where cold lt JT gt gt 0
In order to release available potential energy
(and generate motion), on average, warm air must
rise, cold air sink lt wT gt gt 0