Monitoring glacier surges in the Kongur Tagh area of the Tibetan Plateau using Sentinel-1 SAR data

摘要

Accurate identification of glacier surges aids in promoting a better understanding of the mechanisms of rapid glacier movement and predicting possible surge-related hazards. Surges of 10 glaciers in the Kongur Tagh area of the Tibetan Plateau were examined based on 128 scenes of Sentinel-1 Synthetic Aperture Radar (SAR) imagery with 12-day and 24-day time intervals from 2015 to 2019. To identify the surges, a set of quantifiable multi-feature criteria was used, including higher glacier velocity, surge front position movement and continuous higher velocity at contiguous time intervals based on surge-type glacier characteristics. The results showed that the Karayaylak Glacier surge reported in May 2015 was more likely initiated in summer 2014, and an unreported pulse event occurred in 2019. Another new and complete surge in the Jangmanjiar Glacier from 2016 to 2018 was further identified. Another two pulse events in the Jangmanjiar Glacier and the Kokodak Glacier in 2015 were discovered. The elevation changes from ASTER images and glacier terminus evolution based on Landsat 8 images also provided positive evidence for the occurrence of two surges. In the Kongur Tagh area, the surge type glaciers might have larger areas (above 40 km(2)), longer lengths (above 13 km), lower slopes (below 10 degrees) and higher mean quiescent velocities (above 0.1 +/- 0.05 m d(-1)) than non-surging glaciers. The temperature and precipitation data of ECMWF Re-Analysis 5 (ERA5) showed that the surges in the Kongur Tagh area were mainly induced by thermal and hydrological trigger mechanisms together. (C) 2021 Elsevier B.V. All rights reserved.