Abstract:
Objectives: The Shishapangma region is in the central Himalayas, where glaciers and proglacial lakes are widely distributed. Under global climate warming, the cryospheric environment in this area has undergone remarkable changes. Clarifying the coupling relationship between proglacial lake evolution and the dynamic response of parent glaciers is essential for mountain cryosphere research and glacial lake outburst disaster risk assessment. This study quantitatively analyzes the spatiotemporal variations of typical proglacial lakes and the kinematic characteristics of their parent glaciers to reveal their interaction mechanism.
Methods: Based on high-resolution Planet optical remote sensing and ALOS-1/2 SAR datasets from 2007 to 2020, we extracted the boundary and calculated the area and volume changes of Gangxi Co and Galong Co. The PO-SBAS (Pixel Offset Tracking Small Baseline Subsets) method was adopted to invert the flow velocity and time-series cumulative deformation of glaciers. We further compared the dynamic differences between lake-terminating glaciers and land-terminating glaciers, and analyzed the correlation between lake expansion and glacier deformation, as well as the driving effect of climate warming.
Results: The two proglacial lakes showed a continuous expansion trend from 2010 to 2020, with annual area growth rates of 0.05 km
2/a for Gangxi Co and 0.09 km
2/a for Galong Co. The water body at the glacier terminus changes the mechanical conditions of glacier movement: laketerminating glaciers move much faster than land-terminating ones. During 2014-2019, the average velocity of laketerminating glaciers reached 33.2 m/a, while that of land-terminating glaciers was 22.4 m/a, and both types accumulated deformation over 200 m. There was a significant correlation between proglacial lake expansion and parent glacier deformation, and rising temperature acted as the primary external driving factor.
Conclusions: This study systematically expounds the linkage among proglacial lake expansion, glacier dynamic evolution and climatic factors in the Shishapangma area of central Himalayas. The results can provide scientific support for cryospheric process research and the risk prevention of proglacial lake outburst floods under climate warming.