Modified ESFT Method for Application to Atmospheric Radiation

Abstract

   The exponential sum fitting of transmission function (ESFT) developed by Wiscombe and Evans (1977) is modified so as to be suitable to atmospheric radiation:

1. Unequal data spacing of absorber amount is permitted. This leads to the fitting over a wider range of transmittance.
2. The number of terms of ESFT is reduced by the incorporation of a nonlinear least-squared procedure in the original iteration step.

   The modified procedure is applied to H₂O absorption bands in the infrared (IR) and near-IR regions, and the results are tabulated.