ИСТИНА

Monitoring the atmosphere characteristics is an important task in remote sensing of the environment. In this paper, the question is raised about taking into account the influence of clouds on the characteristics of thermal radiation. The disadvantage of a significant part of most studies in this area is the use of a homogeneous plane-layered model of the cloud layer, ignoring its heterogeneous structure. The study calculates statistical properties of random separated cloudiness. The aim is to analyze the applicability of models for cloud correction during microwave radio sounding of thermal radiation. The result of the work is to determine the parameters that best correspond to the cloud fields of the Earth's atmosphere. During the study, algorithms for generating cloud fields were developed based on two well-known stochastic models of broken cumulus clouds proposed for real cloud distributions obtained empirically. The first one was the Plank model based on the results of processing an extensive database of stereoscopic photographs of clouds in the Florida Peninsula. The second one was proposed in the works edited by Mazin, based on aircraft measurements in Ukraine. Both models used are limited to the consideration of Cumulus-type convection clouds. The assumption of the cylindrical shape of the simulated clouds is applied when calculating the radiation characteristics of fields in the microwave range based on the paper published by Kutuza and Smirnov in 1980. In the microwave range, the influence of scattering processes in a cloudy atmosphere can be neglected. When simulating the radio brightness temperature, it is assumed that the radiometer located on the surface of the Earth, it moves along the edge of the cloud field along the X-axis. The radiometer's field of view is perpendicular to the X-axis, i.e., the direction of movement, and is directed into the cloud field at the zenith angle. The calculation was carried out in the C++ programming language. The distribution of clouds by size was controlled by the Kolmogorov statistical agreement criterion. For the applicability of the calculated values to account for the structure of clouds in the atmosphere, it is necessary to generate model cloud fields comparable in size to real cloud fields in the Earth's troposphere. This results in significant computational costs required for their modeling and analysis. Numerical modeling of the statistical properties of thermal radio emission of separated cloudiness field models implies the need to perform calculations with an ensemble of simulated random fields of a sufficiently large size, which should reach several hundred for each set of parameters, and the use of projections with good resolution, therefore, the optimal use for computing high-performance computers. Numerical experiment shows that with iterative filling of clouds in descending order of their diameter, in an acceptable time to find a suitable random location for each new cloud, it is possible to achieve the maximum percentage of cloud coverage of the plane up to 65-75 \% without the involvement of specialized optimal packing algorithms. As a result, the compliance of the broken cloud cover models with the observational data was verified and the validity of using the proposed models in microwave radiometric sensing are investigated. In addition, the developed algorithms and computer models of cloud fields significantly form a practical basis for further studies of radiation processes in the cloud atmosphere. Two-dimensional (2D) distributions of the brightness temperature of the outgoing thermal radiation of the separated cloudiness fields were calculated. For simplified statistical models of separated cloudiness fields, numerical estimates of the radio brightness temperatures of microwave radiation of the cloud layer are obtained depending on the model statistical parameters.