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HOW DO WE TALK ABOUT RADIATION IN THE ATMOSPHERE?

HOW DO WE TALK ABOUT RADIATION IN THE ATMOSPHERE?. Relationship between Spherical and Cartesian Coordinates. Solid Angle Definition. Irradiance Definition.

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HOW DO WE TALK ABOUT RADIATION IN THE ATMOSPHERE?

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  1. HOW DO WE TALK ABOUT RADIATION IN THE ATMOSPHERE?

  2. Relationship between Spherical and Cartesian Coordinates

  3. Solid Angle Definition

  4. Irradiance Definition F = Irradiance, (also called flux or flux density), is the electromagnetic energy per unit time, per unit area, transported through dA, or deposited on dA. SI units are Watts/m2 when integrated over a distribution function F. (Example: solar flux at the TOA is 1360 W/m2.) F Monochromatic Irradiance, SI units are W/m3.

  5. Monochromatic Radiance Definition I = Monochromatic radiance, is the monochromatic irradiance (measured on a surface normal to the beam) per unit solid angle traveling in a particular direction. This is the most fundamental measure we can use for radiation in the atmosphere.

  6. Irradiance - Radiance Relations Upward irradiance. Note ESPECIALLY the cos term (that gets the normal component of radiance) and the sin term (that helps define the solid angle.)

  7. Irradiance - Radiance Relations Special case: I isotropic, same in all directions, like black body radiation from a surface.

  8. BLACK BODY RADIATION AGAIN: RADIANCE Note especially the units of radiance on the left.

  9. ASIDE: EMISSIVITY OF VARIOUS SUBSTANCES

  10. Irradiance - Radiance Relations Downward irradiance

  11. THE BIG PICTURE: Radiation Heating of the Atmosphere From Oort and Peixoto

  12. ATMOSPHERE HEATING BY RADIATION: The heating rate is the divergence of the net irradiance (or net flux if you prefer). From Oort and Peixoto

  13. ATMOSPHERE HEATING BY RADIATION: The heating rate is the divergence of the net irradiance (or net flux if you prefer). From Oort and Peixoto

  14. ATMOSPHERE HEATING BY RADIATION: The heating rate is the divergence of the net irradiance (or net flux if you prefer). This is the figure caption for the heating rate calculation, and the reference. From Oort and Peixoto 2 problems: 1. Is the assumption of stratosphere radiative equilibrium good? 2. Is it correct to separate out the LW emission from components?

  15. Sun and Satellite Perspective: How do the properties of the surface affect what we see?

  16. Radiance and Irradiance: How do we define radiation? Types of reflection: Can also think of the reflected light as emitted light from different types of surfaces.

  17. Geometry for the BDRF (bidirectional reflection function) S is solar irradiance coming in. I is the reflected radiance.

  18. ENERGY BUDGET: 100% in, 100% out. What does it do along the way?

  19. ASIDE:COMPLEX REFRACTIVE INDICES OF WATER AND ICE. Note that the author DID NOT show that the real part of the refractive index for ice at 2.85 microns is less than 1!

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