THE MATHEMATICAL MODEL OF OPTICAL REMOTE SENSING SYSTEM SIGNAL CONSIDERING BROKEN CLOUDINESS EFFECTS
- Moscow Power Engineering University, Light Engineering Department, Moscow, 111250 Krasnokasarmennaya Street 14, Russian Federation
Keywords: Broken clouds, Synthetic iterations, Quasi two-stream approximation
Abstract. With increasing of the accuracy of measuring equipment for the optical remote sensing in recent years the requirements for speed and accuracy of the algorithms for satellite data processing has greatly increased. It became necessary accurately to account all of the known factors, which affect the signal significantly. At each time, more than half of the planet is covered with clouds, so it is almost always necessary to take measurements into breaks in clouds. Cloudiness is among those factors which affect significantly the signal and its neglect in extreme cases can lead to an error of 140%. Here we propose a new solution of the radiative transfer equation (RTE) for a slab of a turbid medium with consideration of broken clouds. We use the classical approach to solving RTE: complete solution is represented as the sum of the anisotropic and regular parts. We express anisotropic part using small-angle modification of the spherical harmonics method. For the regular part we propose to use quasi two-stream approximation. This method is a special case of the synthetic iterations method. The method is based on splitting the ordinary iteration into two stages. At the first step one of approximate methods is used, and on the second step one ordinary iteration is used. We use two-stream approximation as an approximate method. In this paper we proposed a solution for the simplest case of broken clouds - cylindrical hole in the slab. Comparison of the algorithm was performed with established program MDOM, and showed good agreement.