Monte Carlo Simulation of the Solar Radiation Transfer in a Cloudy Atmosphere with the Use of Graphic Processor and NVIDIA CUDA Technology

Problems of improving the efficiency of the Monte Carlo numerical simulation of solar radiation propagation in the Earth’s atmosphere by transition from sequential to parallel computations are discussed. A new parallel algorithm oriented to a computational system with the NVIDIA CUDA enabled graphics processor is presented. The efficiency of parallelization is analyzed by an example of calculating the upward and downward fluxes of solar radiation both in a vertically homogeneous and in an inhomogeneous model of the atmosphere. The results of testing the new algorithm under various atmospheric conditions including continuous single-layered and multilayered cloudiness are presented, with allowance for selective molecular absorption and without regard to it. The results of testing the code using video cards with different computational capabilities are analyzed. It is shown that the changeover of computing from conventional PCs to the architecture of graphics processors gives more than a hundredfold increase in performance and fully reveals the capabilities of the technology used.