Hydrological impacts of interannual variations in surface soil freezing processes in the upper Nu–Salween River basin

Abstract

The upper Nu-Salween River basin in the Tibetan Plateau is mainly covered with seasonal frozen soils. We used daily surface freeze-thaw states, detected from Special Sensor Microwave/Imager (SSM/I) daily brightness temperature data, to analyze the variations in surface freeze-thaw states and the relationship with air temperature. We also examined baseflow to explore the influences of interannual variations in the start time of soil freezing on hydrological processes. The results showed that (1) interannual air temperature fluctuations led to differences in the area and start time of surface freezing. When surface soil froze, flow was mainly dependent on existing groundwater storage. (2) The interannual variation in the surface freezing time directly affected the flow generation processes. When soil water froze and remained in the frozen layer, it was hard to generate surface flow, so flow mainly consisted of baseflow, causing the proportion of the baseflow in the total flow to gradually increase. (3) The surface freeze-thaw states obtained from the passive microwave remote sensing data may be applied to support further research on the hydrological impacts of freeze-thaw cycle variations in plateau mountain basins.

Climate change impacts and adaptation to permafrost change in High Mountain Asia: a comprehensive review

“…This was also found for long term data between 1960 and 2014, due to an increase in baseflow as precipitation increased and maximum thickness of the seasonally frozen ground decreased (Qin et al 2016). The increase in the contribution from groundwater during freezing days was also found in the far southeastern part of the Plateau (Luo et al 2020). However, an increase in ground temperatures has also resulted in a decrease in winter runoff elsewhere (Gao et al 2016) as well as an increase in spring and decrease in summer (Tian et al 2016).…”

Glacier area changes in the Nujiang-Salween River Basin over the past 45 years

“…The geographic environment and climatic conditions are particularly complex in this region. The altitude of the study area ranges from 3000 to 6000 m, with 90% of its area lying above 4000 m (Luo et al, 2020b). The climate in the NSRB is primarily affected by the Indian monsoon in summer, leading to humid and warm summers, and mid-latitude westerlies in winter that render it cold and dry during this season (Lan et al, 2014).…”