Outgoing longwave radiation and its diurnal variation from combined ERBE and Meteosat observations 1. Estimating OLR from Meteosat data

Radiative transfer calculations show that measurements in two relatively narrow spectral domains, corresponding to the atmospheric infrared window and to a band of water vapor absorption, can account for nearly all of the variance of outgoing longwave radiation integrated over the entire thermal spectrum. Statistical analyses of simultaneous colocated Meteosat radiance and Earth Radiation Budget Experiment (ERBE) radiant exitance data, for the month of November 1984 and April and July 1985, yield regression coefficients for estimating longwave radiant exitance M_LW from radiances observed in the Meteosat infrared (IR) window and water vapor (WV) channels, with root-mean-square errors of the order of or less than 10 W m^-2. -from Authors