Abstract
One year of longwave radiation data from July 1975 through June 1976 from the Nimbus 6 satellite Earth Radiation Budget (ERB) experiment is analyzed by representing the longwave radiation field by a spherical harmonic expansion. The data are from the wide field-of-view (WFOY) instrument. Results show that the limit of the spherical harmonic representation is 12th degree, based on degree valiance plots from 12 months. Degree variance plots also show that most of the power is in the lower degree terms. The axisymmetric (zonal) terms dominate with their coefficients representing approximately 80% of the degree variance. Contour maps of the radiation field show the geographical distribution of earth-emitted radiant exitance (W m−2) and reveal areas of high and low emitted radiation. The analysis also shows differences between the Northern and Southern Hemispheres which is presumably due to land/ocean distribution.
