Radiative Transfer cont'

1
Radiative Transfer (cont.)

• First-study abroad guest lecture

2
Solar Radiation Budget

• Some in reflection, absorption, transmittance
  (RAT100)
• 30 albedo (reflectance)
• Dark and rough surfaces, absorb more
• Scattering (blue sky)
• Certain wavelengths of light are scattered more
  efficiently than others

3
Scattering

• Rayleigh scattering and Mie scattering
• Rayleigh scattering- wavelength of light is
  similar to the size of the particle doing the
  scatteringblue light is similar to O2 and N2,
  scattered most efficiently when sun is overhead
• Absense of color at night
• Mie scattering- size of the particles doing the
  scattering much larger than vis. light(water,
  dust, etc.) (white hint to sky) (radar
  applications)

4
Shift gears to pressure, winds, and moisture

• All factor in the density of the air
• Revisit temperature
• Temp proportional to KE
• Pressure
• Force per unit area exerted by gravity, molec.
  motions (1013.25 hPa (mb)) Torricelli
• Relationship between two

5
Relationships

• Boyles Law
• PressureVol constant
• Molecules constant, shrink container
• Charles Law
• TempConstantVol
• Gas Law
• PrhoTRd
• Rhodensity, Rd dry gas constant

6
Pressure Distribution

• Low pressure near equator generally
• Tropics, high pressure
• Band of lower pressure around subpolar region
• High pressure at the poles
• AT THE SURFACE

7
500 mb Patterns/PGF

• 500 mb about half the amount of the atmosphere,
  can get a rough idea of jets
• Higher heights in equatorial regions (atmos
  thicker), poles lower
• Drive to equilibrium, mass from equator needs to
  be spread toward the poles
• Tight height contours or pressure contours
  (isobars) represent greater change (gradient)
• Force needs to be directed toward area of low
  pressurePressure Gradient Force (PGF)

8
Lows and Highs

• Flow is clockwise around a high in N.H.
• At the surface due to friction the flow is
  directed outward from H (divergence)
• Low pressure counterclockwise in N.H.
• Friction at the sfc makes flow directed inward to
  L (convergence)
• Cyclonic is for L in both hemisphere
• Anticyclonic is for H in both hemisphere
• Clockwise and counterclockwise switched

9
Next Time

• Equation of motion in simple form, qualitative