ATMOSPHERE HEATING RATE: CLOUD FREE ATMOSPHERE

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ATMOSPHERE HEATING RATECLOUD FREE ATMOSPHERE
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Words and Equation from Petty Radiative Heating
Rate
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Heating Rate Due to Absorption (positive) and
emission (negative) by gases in the atmosphere.
Cloud free atmosphere. (Wallace and Hobbs pg 139.)
Solar radiation Solid curves. Terrestrial
radiation Dashed curves. Heavy Black
Combined effect of solar and terrestrial
radiation. Notes Stratosphere near balance. CO2
cooling, O3 heating. Troposphere, water vapor
dominates, with mostly IR cooling and some solar
heating. BALANCE Achieved by addition of latent
and sensible heat from the surface. The surface
is heated by absorption of solar and IR radiation.
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From Petty. Tropical Atmosphere.
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From Petty. Total heating, tropics, dependent on
sun angle.
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From Petty.
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From Petty, dependence on geographical location.
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ATMOSPHERE HEATING RATECLOUDY ATMOSPHERE
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Schematic of Cloud Heating and Cooling Effects
Wallace and Hobbs Pg 139.
IR cooling at cloud top and heating at cloud base
tends to increase the lapse rate, promoting
convection. Daytime heating by solar radiation
heats cloud tops, suppressing convection.
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IR Cooling Rates(from Liou)
Messages Clouds are good absorbers and emitters
of IR radiation. Solar heating most at cloud
top, countering cloud top cooling in the IR,
during day. Cooling rate is from the vertical
divergence of the net irradiance absorbed and
emitted.
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OVERALL RADIATION BALANCEIncreased solar
absorption in troposphere (lowers albedo) -gt
increased IR from atmosphere to gnd, gnd to
atmosphere, atmosphere to space (response to
lowering albedo).
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Radiation Pathways and Budget(342 W/m2 is the
total Solar 1,370 W/m2 averaged over the Earths
Surface)
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Radiative Balance Wallace and Hobbs Ch10.
100 units solar solar radiation 342 W/m2.
BlackSolar Radiation, Red IR Radiation.
70 net emitted
70 net absorbed