Presentation on theme: "Metr 200/201 Thursday 2/22/01 Some more on OLR and ISR."— Presentation transcript:
Metr 200/201 Thursday 2/22/01 Some more on OLR and ISR
The Stefan-Boltzmann Equation Relates outward energy flux to temperature of a black body You used this relation to calculate the monthly average emitting surface temperatures from the Climate Diagnostics Bulletin. The latest Climate Diagnostics Bulletins are available online herehere Key assumption: emitting surface acts like a black body"
Black Bodies Are perfect absorbers and emitters of electromagnetic radiation For practical purposes you can consider thick clouds and earths surface (land and water) as black body emitters of radiation Thin clouds - and the clear atmosphere are most definitely not black bodies - they are selective absorbers of radiation
Selective absorbers /emitters Gases (and thin clouds) are only able to absorb and emit radiation within certain wavelength ranges. For other wavelengths, gases do not absorb or emit any radiation - in other words, they are transparent to radiation in those wavelengths. Black bodies, on the other hand absorb radiation over all wavelengths. In other words - black bodies are opaque.