Pioneering remote sensing in the USSR. 2. Global spherical models of radiation transfer

This paper presents a brief overview of the first investigations of the Earth's radiation field, aerosol and ozone layers and the transfer function of the atmosphere from manned space satellites (Soviet Sputniks) concerning remote sensing problems of the Earth's surface. Mathematical tools were created for these investigations and multidimensional spherical and plane models of radiation transfer in the Earth-Atmosphere system were elaborated. These investigations were conducted under Professor K. Ya. Kondratyev's leadership and with his direct participation. The perspectives of a global spherical model of radiation transfer in optical remote sensing data analysis are outlined. Original universal techniques are proposed for the first time for radiation transfer modelling in the Earth-Atmosphere system. The approach is based on the construction of generalized solutions in the form of functionals, the kernels of which are given by the influence functions of the atmosphere. These influence functions with different aerosol and molecular characteristics of scattering and absorption, as well as the different radiation regimes, can thus be calculated by different techniques in various approaches to radiation transfer theory.