. " Emissivity is the ratio of the power emitted by an object to the power that would be emitted by a perfect black body having the same temperature as the object. The emissivity is assumed to be an integral over all wavelengths, unless a coordinate of radiation_wavelength or radiation_frequency is included to specify either the wavelength or frequency. The surface called \"surface\" means the lower boundary of the atmosphere. " . . . "surface microwave emissivity" . "Climate and Forecast (CF)" . .