Elements of the Sun; Solar Radiation

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Chapter 3 Atmospheric Radiative Transfer and
Climate

• To date, we have learned
• The greenhouse effects, through understanding the
  simplest greenhouse model,
• The aerosols effects on radiation, clouds, and
  temperature,
• The global energy balance, that shows how global
  energy components are budgeted at the TOA, in the
  atmosphere, and at the surface.
• Now, we will further learn here
• How greenhouse gases affect radiation,
• How clouds influence radiation,
• How they together impact temperature profiles,
  and
• What is cloud radiative forcing?

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Recap of the greenhouse effect
Solar radiation
Long-wave radiation
236 Wm-2
236 Wm-2
Equivalent T 255 K (-18ºC)
390 Wm-2 T 288 K (15ºC)
Do you know where is this 236 coming from?
 
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How greenhouse gases affect radiation?
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How does the atmosphere affect radiation?
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Nitrous Oxide
Atmospheric Absorption
Solar radiation passes rather freely through
earth's atmosphere. Earth's re-emitted longwave
energy either fits through a narrow window or is
absorbed by greenhouse gases and re-radiated
toward earth.
Methane
Ozone
Absorption (100)
Water Vapor
Carbon Dioxide
UV
IR
Total Atmo
Wavelength
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Through this atmospheric window, satellite
sensors are designed to see, observe, measure
or monitor the Earths surface.Spectra of
outgoing radiation from Earth observed by IRIS on
Nimbus 3
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What are the dominant gases in the atmosphere?
N2 and O2
Are they greenhouse gases?
Why not?
Diatomic molecules like N2 and O2 have no
permanent dipole moment and no bending moment and
so have no capacity to absorb or emit low energy
thermal radiation.
What are greenhouse gases?
CO2, N2O,H2O, O3
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Nuclear Configuration and Permanent Dipole
Movement
Symmetric, linear molecules (Both ends look the
same)
Nonlinear or bent
Have pure rotation bands
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Vibrational Modes of Diatomic and Triatomic
Molecules
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How do greenhouse gases affect the temperature
profile? (1/2)
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How do greenhouse gases affect the temperature
profile? (2/2)
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Thermal equilibrium profiles
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How do clouds affect radiation? 1. Liquid water
path and solar zenith angle
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How do clouds affect radiation? 2. Cloud particle
size
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How do clouds affect radiation? 3. Cloud phase
(water versus ice)
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How do clouds affect the temperature profile?
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How do clouds affect net radiation at TOA?
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How do clouds affect shortwave radiation?
Cloud forcing average ( or cloudy) cloud-free
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How do clouds affect longwave radiation?
Cloud forcing cloudy cloud-free
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How do clouds affect net radiation?
Cloud forcing cloudy cloud-free NET SW LW
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How do clouds distribute globally?
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How are clouds measured from space?
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High clouds measured from space?
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Low clouds measured from space?
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Summary

• Now, we have learned
• How greenhouse gases affect radiation,
• How clouds influence radiation,
• How they together impact temperature profiles,
  and
• What cloud radiative forcing is.

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Seasonal patterns of shortwave cloud radiation
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Seasonal patterns of longwave cloud radiation
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Seasonal patterns of net radiation cloud forcing