PHY2505 - Lecture 19

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PHY2505 - Lecture 19

• 1-D climate models

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Overview

• Last lecture
• Review of Liou
• IPCC definitions of radiative forcing
• This lecture
• 1-D radiative-convective climate models
• IPCC results
• Final lecture
• Climate and planetary atmospheres

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Hierarchy of models simple ideas
0-D 1-D2-D 3-D Global mean
Radiative- Energy GCMs effective
convective balance temperature
Balance TOA. at every. Include. Include
Fs FIR level N-S flow feedbacks
Radiative transfer
Equations of motion
Equations for water vapor cloud
Thermodynamic equation
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Hierarchy of models
0-D 1-D2-D 3-D Global mean
Radiative- Energy GCMs effective
convective balance temperature
Radiative transfer
Equations of motion
Equations for water vapor cloud
Thermodynamic equation
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1-D radiative-convective models
Convection significantly reduces surface ( low
level) temperature
Radiative transfer
Equations of motion
Equations for water vapor cloud
Thermodynamic equation
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1-D radiative-convective models
CLEAR CLOUDY
Radiative transfer
Equations of motion
Equations for water vapor cloud
Thermodynamic equation
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1-D radiative-convective models
Convective adjustment scheme
Radiative flux divergence due to convection
Static stability
From first law of thermodynamics, see Liou p467
Then local rate of change of temperature from
Equations for water vapor cloud
Thermodynamic equation
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IPCC results
Equations for water vapor cloud
Thermodynamic equation
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IPCC results well-mixed gases
FRAD calculated according to RTE
FS-FIR IPCC results from 2001 differ from
IPCC 1995, 1992 because of new HITRAN data base.
Addition of thousands of lines cause change in
forcing results of 1.5 for doubling of CO2,
greater differences for less known species
Equations for water vapor cloud
Thermodynamic equation
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IPCC results well-mixed gases
TOTAL FORCING SAR 2.45 - 15 Wm-2 IPCC 2001
2.43-10Wm-2 Doubling of CO2 3.7Wm-2
Equations for water vapor cloud
Thermodynamic equation
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IPCC results ozone
Highly variable Stratospheric ozone loss causes
a negative forcing Cooling from stratosphere
more important than increased solar transfer to
surface uncertainties due to difficulty in
obtaining vertical profiles
Equations for water vapor cloud
Thermodynamic equation
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IPCC results ozone
Highly variable Tropospheric ozone increases
causes a positive forcing Difficulty estimating
magnitude due to uncertainty of how pollution
will effect vertical distribution
Equations for water vapor cloud
Thermodynamic equation
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IPCC results ozone
Equations for water vapor cloud
Thermodynamic equation
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IPCC results aerosols
Direct effects scattering and absorption Indirect
cloud
Equations for water vapor cloud
Thermodynamic equation
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IPCC results aerosols
Equations for water vapor cloud
Thermodynamic equation