The seasonal snowpack plays an essential role in the water resources budget of the global mountainous area and provides freshwater supply for over 1/6 of the world's population (Barnett et al., 2005;, which has a profound effect on the food production of irrigated agriculture and snowmelt runoff regimes in the snow-dominated basin (Qin et al., 2020). It also strongly affects regional climate system, alpine phenology, and biogeochemical processes through regulation of the land-atmospheric exchanges of water and energy (Arndt et al., 2020;Tomaszewska et al., 2020;Zhang, 2005). In addition, snow attracts recreational activities and is an important resource of winter tourism (Deng et al., 2019), but it also causes snow-related disasters, such as snow avalanches and snowmelt flooding (Ballesteros-Cánovas et al., 2018;Schweizer et al., 2003). Although the role of snow is irrefutable, present approaches show a large uncertainty regarding snow mass estimation in a global mountainous area due to the presence of orographic barriers, its strong vertical and horizontal variability, diverse vegetation cover, and representative sites for snow measurement (Dong, 2018;Dozier et al., 2016;Mudryk et al., 2015). The accuracy of snow mass map based on in-situ observations interpolation methods depends on the number and representativeness of the ground observations, while a sparse network of snow observations usually exists in the mountainous environment, especially in the area with dense vegetation and a complex topography (Dozier et al., 2016;Mortimer et al., 2020). The passive microwave sensors could provide a nearly real-time global snow mass