Spatial And Temporal Distribution Simulation Of Mountain Shadow In High Asian Glacier Region Its Influence On Solar Radiation

In the complex alpine mountain terrain conditions,due to the surrounding terrain occlusion leads to the formation of mountain shadow.In previous studies,the temporal and spatial differences of solar radiation caused by the shadowing effect of mountain shadows are rarely considered.In order to quantitatively analyze the impact of temporal and spatial heterogeneity of mountain shadow on solar radiation.Based on ray tracing algorithm and DEM data,this paper simulates the spatial distribution of mountain shadow in high Asian glacier region.The accuracy of the simulation results of the ray tracing algorithm is verified based on the confusion matrix and the valley coefficient,and the mountain shadow obtained by visual interpretation and support vector machine.Based on multiple linear regression analysis,the influence of mountain shadow on solar radiation under different regional conditions is explored.The main conclusions are as follows :1)In each verification area,the accuracy of mountain shadow mapping simulated by ray tracing algorithm is between 45 % and 76 %,the user accuracy is between 73 % and 94 %,the overall classification accuracy is between 82 % and 91 %,the Kappa coefficient is between0.46 and 0.73,and the valley coefficient is between 0.49 and 0.80.As the solar elevation angle increases,the accuracy of mountain shadow simulation decreases.2)Shadows in the Altai Mountains and East Tianshan Mountains are most seriously covered.The average annual shading duration was 2021 hours and 1811 hours,respectively.In the Tibetan Plateau,the eastern Himalaya is the lightest.The average annual shading duration was 1159 hours and 1172 hours,respectively.3)The influence of mountain shadow on solar radiation in Altai Mountain and Pamir Plateau is large,and the annual solar radiation changes are 246 MJ / m2 and 171 MJ / m2,respectively.The annual solar radiation changes in the eastern Kunlun Mountains and Qilian Mountains are small,67 MJ / m2 and 80 MJ / m2,respectively.4)The annual solar radiation variation is 274 MJ / m2 and the annual solar radiation variation range is 5.01 % in the area where the mountain shadow is over 1946 h;the annual solar radiation variation is 46 MJ / m2 and the annual solar radiation variation is 0.54 % in the region with shadow shading time less than 996 h.5)The influence of mountain shadow on solar radiation is inversely proportional to latitude,and is proportional to the shading time and altitude of mountain shadow.Low latitude,high sea...