Parameterization of the solar absorptivity and transmissivity using Nimbus II reflectance data.

Abstract

Satellite data first became available in the 1960's making solar budget calculations more feasible. In this study, satellite measurements of reflected solar insolation from NIMBUS II were combined with simultaneous pyrheliometer readings of transmissivlty over North America to provide the basis for computation of the atmospheric absorptivity. In the statistical parameterization of the absorptivity, such readily available data as water vapor mass and satellite reflectance were introduced as independent variables in the regression equations. Correlation coefficients between observed regression-determined absorptivities and transmisslvities were computed based upon an initial total of 235 data-samples, and the results interpreted. The conclusion was twofold: (1) A new suggested insolation-budget model is proposed for computation of absorptivity; (2) the desirability of deriving a statistical parameterization for cloud-cover at grid points in terms of satellite-observed reflectances and window-channel temperatures is shown.