Emissivities

Take two large disks with emissivities of unity, one at temperature T1 the other at T2, the second being higher than the first. ❋ EliRabett (2008)

In the literature one can find emissivities for old snow (eps = 0.82) and fresh snow (0.99). ❋ EliRabett (2008)

Most emissivities over the wavelengths radiated by the earth are in excess of 95% and many of the common surfaces are over 98 or 99% absorptive. ❋ Unknown (2007)

So the emissivities/absorptivities can be quite different for the two phenomena. ❋ Unknown (2007)

The emissivities of the various substances vary quite a bit. ❋ Unknown (2007)

The equivalent chart for water vapor and a correction chart for the water vapor/carbon dioxide overlap so the emissivities can be combined can also be found on the web if you look hard enough, in answer to #211. ❋ Unknown (2007)

I have posted a graph of the Hottel emissivities for CO2 at UKweatherworld on page 6 of the debate thread. ❋ Unknown (2007)

Emissivities are determined by weighting wavelength-dependent emissivities over subgrid soil, vegetation, roads, rooftops, and water. ❋ Unknown (2006)

Put simply, material groups can be used to describe the optimum wavelengths for highest object emissivities and therefore the most stable results. ❋ Unknown (2010)

Earth’s emissivity varies greatly at different wavelengths, and the emissivities at different wavelengths change differently in the face of rising CO2 concentrations. ❋ Unknown (2006)