Atmospheric Transmission Beer's Law

3/31/10• β e = β a + β sExtinction of radiation• The extinction coefficient (β e ) is the sum of an absorptioncoefficient (β a ) and a scattering coefficient (β s ) – all have unitsof inverse length (m -1 )• For milk, β a ≈ 0 so β e ≈ β s ; for ink β s ≈ 0 so β e ≈ β a• To characterize the relative importance of scattering andabsorption in a medium, the single scatter albedo (ω) is used:• ω = 0 for a purely absorbing medium (ink), 1 in a purelyscattering medium (milk)Based on their appearance what would you concludeabout the spectral dependence of β e and ω for……• A cloud?Highly reflective ofsunlight, suggesting thatthe SSA is very close toone. Clouds are white,rather than some othershade, suggesting thatthe SSA and extinctioncoefficient don’t dependmuch on wavelengthwithin the visible band.5