Monitoring Rock Desert Formation Caused by Ice-Snow Melting in the Qinghai-Tibet Plateau Using an Optimized Remote Sensing Technique: A Case Study of Yushu Prefecture

The rapid and effective identification of the spatial distribution of rock deserts in ice- snow melting areas can provide useful information for the prevention of natural disasters. In this study, Landsat TM/OLI were used to track the evolution of snow lines in the snow melting areas of Yushu Tibetan Autonomous Prefecture of the Qinghai-Tibet Plateau (hereinafter referred to as Yushu Prefecture) during the last 30 years. A total of seven extraction schemes were used to classify the rock desert in the ice-snow melting area by remote sensing. Our results show that: (1) The accuracy of the multi-index factor compound analysis and object-oriented classification compound method was the highest. This method can provide a rapid and efficient reference scheme for rock desert extraction in the plateau ice-snow melting area. (2) The combinations of two single methods with higher accuracy can further improve the total accuracy. If a single method with lower accuracy is involved in the multi-method fusion, the accuracy of the method with lower accuracy can be improved. (3) In the past 30 years, there has been a large amount of ice-snow melting in Yushu Prefecture. The ice-snow melting area accounts for 53.78% (1451.04 km(2)) of the ice-snow area, and the bare rock and bare stone in the rock desert account for 63.77% of the total area of the ice-snow melting area. Bare sand and bare soil area account for 30.27% of the total area of ice and snow melting area.