Evaluating the different responses to climatic factors between snow water equivalent and snow cover area in the Central Tianshan Mountains

Alpine snow is an important part of the water cycle in arid/semiarid regions and has a great influence on runoff and ecosystems. In this study, both optical and passive microwave remote sensing data were used to characterize the vertical distribution of snow cover area (SCA) and snow water equivalent (SWE) on the north slope of Central Tianshan Mountain, northwest China, focusing on exploring the different spatial–temporal characteristics between SCA and SWE, as well as their different responses to climatic factors at different altitudes. The results show that (1) the SCA and SWE have similar vertical distribution characteristics but show different changing rates and changing directions over time at different altitudes. (2) In the snow accumulation period and snowmelt period, the correlation relationships between precipitation/temperature and SCA are the same (positive or negative) as those between precipitation/temperature and SWE at low-middle altitudes but opposite at high altitudes. (3) The influence of precipitation/temperature on SWE has a linear relationship with altitude but not with SCA. (4) The relative importance of precipitation/temperature for SCA is the same as that for SWE at different altitudes. The results illustrated the different vertical responses to climatic factors between SCA and SWE, which could be beneficial to predicting the changes in mountain snow under the climate change scenario.