Changes in the glacier extent and surface elevation in Xiongcaigangri region, Southern Karakoram Mountains, China

The recent evolution of the Karakoram glaciers, widely acknowledged as peculiar, remains poorly understood. The Xiongcaigangri region is in the south of Karakoram, and its glacial melt water has a significant impact on the local water supply and ecosystem. In this work, glacial changes in the Xiongcaigangri region were detected based on topographic maps and Landsat MSS/TM/ETM+/OLI, SRTM4.1 DEM and Glas/ICESat remote sensing data and GIS techniques. The results show that from 1968 to 2013, the total glacier area decreased from 181.10 km(2) to 178.47 km(2), an overall loss of 2.63 km(2), or 1.45% of the entire 1968 glacial area. The inverse relationship between the retreating area and the change rate indicates that small glaciers may be retreating faster. The main glacial melting occurred below 6500 m a.s.l, and the reduction of 2.62 km(2) accounts for 99.62% of the total glacial retreat in the area studied. The very slight reduction of 0.01 km(2) over 6500 m a.s.l accounts for only for 0.38% of the total glacial retreat in the area studied. The results also show that the glacier areas are decreasing on all slopes, and larger area losses have been observed on smaller slopes, whereas smaller area losses have been observed on the larger slopes. The different aspects of the study all showed glacier retreat taking place between the period from 1968 to 2013. The largest area decrease is in west, and the area lost in the other aspect was comparatively small. Total glacier mass loss in the Xiongcaigangri region is estimated to be (10.97 +/- 22.39) 10(8) m(3) w.e. between 1968 and 2000. The average elevation loss estimated from the ICESat and 2000 SRTM difference was from -4.69-3.40 m per year, and the average elevation loss between SRTM and 1968DEM was from -0.92 to 0.66 m per year. Increasing temperatures along with decreasing precipitation was determined to be the primary factor driving the glacier retreat in the Xiongcaigangri region. (C) 2014 Elsevier Ltd and INQUA. All rights reserved.