Evolution of snow cover and snow depth in the Naqu River Basin based on the MODIS products

The MODIS snow product has been utilized to investigate the evolution of snow cover and snow depth in the Naqu River Basin. The findings indicated that approximately 50% of the basin experiences more than 50 days snow-covered annually. The distribution of snow cover extent is not uniform throughout the year, and the maximum snow cover extent reached 77,000 km² on a daily basis. The region of perennial snow cover is located in the middle and lower high mountain areas of the basin. Furthermore, the overall trend of snow depth in the basin is indicated by a decrease of -0.49 millimeters per annum. The region with the maximum multi-year mean snow depth 101.7 millimeters is concentrated in the northern part of the basin, and the region with the minimum multi-year mean snow depth 1.8 millimeters is located in the western part of the basin. Snow depth is negatively correlated with temperature, but positively correlated with snowfall. Additionally, changes in snow depth are observed to occur with a certain lag in comparison to changes in temperature and snowfall.