Monitoring glacier terminus and surface velocity changes over different time scales using massive imagery analysis and offset tracking at the Hoh Xil World Heritage Site, Qinghai-Tibet Plateau

Abstract

Due to climate change, the Qinghai Hoh Xil World Heritage Site is under a significant threat from glacier melting and related glaciological hazards. A comprehensive understanding of glacier change trends will be important for launching the policy of sustainable development and for taking precautionary actions when abnormal glacier movements are recognized. Current research neglects the phenomenon in glacier movement monitoring, where the glacier variation pattern responds abnormally over different time scales. In our work, the most advanced techniques, Google Earth Engine (GEE) and offset tracking (OT), were utilized to construct and compare long-term series of glacier changes over decadal and annual scales, respectively. In total, 264 glaciers were extracted, and similar trends, namely, general degradation except one glacier expressing a fast increase in XinQing Feng (XQF), slow recession in Malan (ML), and complex and seasonal degradation in Galadandong (GLDD), were confirmed by GEE and OT. By comparing the performance of these two methods, GEE shows its merits when applied to detect the large magnitude of geomorphic and glaciological change with an average uncertainty error of approximately 8 m/yr, while OT is more suitable for detecting regular and continuous displacement with high accuracy up to 1 m/yr. Our results highlight the asynchrony of glacier variation within different time scales and the significant complementary role of integrating GEE and OT approaches for world heritage site conservation and protection.

Keywords

• Glacier monitoring
• Google Earth Engine imagery analysis
• Offest-tracking
• Hoh Xil World Heritage Site