Abstract: Snow cover depth is a necessary parameter for the operation of weather and hydrological models,and its monitoring is of importance in predicting snow melting runoff,managing water resources and preventing and controlling flood. Microwave remote sensing can be used to invert snow cover depth on different scales and provide the effective snow cover parameters for climate model and water cycle on global or regional scale. The available inversion algorithms of snow cover depth are often based on microwave remote sensing,in which the effects of land covers are considered only,but the comprehensive influence of topographical factors on inverted results is not considered. In the mountainous areas with undulating terrain,the surface signals observed with microwave radiometer are affected by terrain,and the surface energy is redistributed. The energy redistribution can not only cause the measurement error of sensor,but also can change the microwave scattering and radiation on land surface,and the inversion accuracy of the key surface parameters is influenced. In order to improve the accuracy of snow cover depth inversion in mountainous area,the effects of slope and aspect on snow cover depth inversion were studied in this paper,the slope and aspect corrections were added in inverting snow cover depth with microwave remote sensing,and a microwave radiation model was developed based on the topographic effect. A snow cover depth retrieval algorithm based on topographic correction was proposed. Experimental results showed that RMSE of snow cover depth inversion without terrain correction was 10.41,RMSE was 7.22 after terrain correction,and the accuracy of snow cover depth inversion was improved to some extent.

Key words: topographic correction, microwave remote sensing, snow cover depth, remote sensing inversion