The Simulation of Extraterrestrial Solar Radiation Based on DEM in Zhangpu Sample Plot and Fujian Province

The study establishes DEMs and the computer models of daily extraterrestrial radiation in Zhangpu sample plot and Fujian province and annually extraterrestrial radiation in Fujian province using GIS. The results indicate that the daily extraterrestrial radiation is mainly 17-18MJ/m² in Zhangpu, the one is mainly 14-18MJ/m² and the annually extraterrestrial radiation is mainly 5000~7000 MJ/m² in Fujian province. The influence of topographic feature is significant, in general the solar radiation in the chine is bigger than the one in the valley, and the one in the sunny slope is bigger than in the shady slope, the high radiation value appears primarily in the sunny slope with the chine as demarcation line. The method can extract daily and annually extraterrestrial radiation with high precision and speediness at small and moderate scales which donpsilat take cloud into consideration. The orientation of future research is to improve precision by RS images.