The Atmosphere: Part 5: Large-scale motions
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Transcript of The Atmosphere: Part 5: Large-scale motions
![Page 1: The Atmosphere: Part 5: Large-scale motions](https://reader035.fdocuments.net/reader035/viewer/2022062321/56813152550346895d97cd4e/html5/thumbnails/1.jpg)
The Atmosphere:Part 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
Implied energy transport: requires fluid motions to effect the implied heat transport
Observed radiative budget
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Roles of atmosphere and ocean
Trenberth & Caron (2001)
net
ocean
atmosphere
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Basic dynamical relationships
dudt
2 u p friction
Ω
φ
u
ΩΩsinφ
dudt
fv 1
px
dvdt
fu 1
py
f 2 sin
Equation of motion
Shallow atmosphere:
p z x,y
g
1
px z
g zx p
1
py z
g zy p
} z - coordinates
dudt
fv g zx
dvdt
fu g zy
} p - coordinates
![Page 6: The Atmosphere: Part 5: Large-scale motions](https://reader035.fdocuments.net/reader035/viewer/2022062321/56813152550346895d97cd4e/html5/thumbnails/6.jpg)
Basic dynamical relationships
dudt
2 u p friction
Ω
φ
u
ΩΩsinφ
dudt
fv 1
px
dvdt
fu 1
py
f 2 sin
Equation of motion
Shallow atmosphere:
p z x,y
g
1
px z
g zx p
1
py z
g zy p
} z - coordinates
p
x zx
p
z x z
0 p px z
x p z x
z
zx p
zx
px z
/p z x
1g
px z
![Page 7: The Atmosphere: Part 5: Large-scale motions](https://reader035.fdocuments.net/reader035/viewer/2022062321/56813152550346895d97cd4e/html5/thumbnails/7.jpg)
Basic dynamical relationships
dudt
2 u p friction
Ω
φ
u
ΩΩsinφ
dudt
fv 1
px
dvdt
fu 1
py
f 2 sin
Equation of motion
Shallow atmosphere:
p z x,y
g
1
px z
g zx p
1
py z
g zy p
} z - coordinates
dudt
fv g zx
dvdt
fu g zy
} p - coordinates
![Page 8: The Atmosphere: Part 5: Large-scale motions](https://reader035.fdocuments.net/reader035/viewer/2022062321/56813152550346895d97cd4e/html5/thumbnails/8.jpg)
fu g zy
fv g zx
Geostrophic balance
dudt
fv g zx
dvdt
fu g zy
Ro UfL
1
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fu g zy
fv g zx
Geostrophic balance
dudt
fv g zx
dvdt
fu g zy
p z x,y
g
zp x,y
1g R
gp T
2zpx
Rgp
Tx
up
Rfp
Ty
vp
Rfp
Tx
thermal wind shear balance
Ro UfL
1
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Rotating vs. nonrotating fluids
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Rotating vs. nonrotating fluids
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Rotating vs. nonrotating fluids
Ω
φ
u
ΩΩsinφ
f = 0
f > 0
f < 0
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Atmospheric energetics:where does the energy of atmospheric motions come from?
Flattening density/temperature surfaces always reduces potential energy
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Atmospheric energetics:where 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 energetics:where 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:
< JT > > 0
![Page 16: The Atmosphere: Part 5: Large-scale motions](https://reader035.fdocuments.net/reader035/viewer/2022062321/56813152550346895d97cd4e/html5/thumbnails/16.jpg)
Atmospheric energetics:where 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:
< JT > > 0
In order to release available potential energy (and generate motion), on average, warm air must rise, cold air sink:
< wT > > 0