Multiple solutions of the inverse problem of retrieval of scattering-atmosphere optical parameters from remote measurements

Abstract

Space-borne measurements of the intensity of outgoing reflected and scattered short-wavelength radiation for a few viewing angles (multi-angle measurements) are used to determine the optical parameters of a cloudless atmosphere. In this case, it is proposed to formulate the problem of complex (simultaneous) retrieval of extinction and scattering aerosol optical parameters on the basis of radiation transfer equations with the minimum use of a priori information. The simplest variant is considered within the framework of the standard model of illumination of a plane-parallel, vertically-uniform atmosphere by parallel solar rays. The optical parameters averaged over the entire thickness of the atmosphere are sought in this case. The scattering phase function is approximated by one-parameter functions. The parameter is equal to the phase function mean cosine. A numerical neural-network algorithm and an analytical single-scattering method were used to solve the problem within the framework of the considered simplest model. In the first case, the resulting solution differs only slightly from the predetermined a priori model. In the second case, multiple solutions are found.