Topography-Related Glacier Area Changes in Central Tianshan from 1989 to 2015 Derived from Landsat Images and ASTER GDEM Data

摘要: Studies have investigated the glacier projected area (2D Area) on a horizontal plane, which is much smaller than topographic surface extent (3D in steep terrains. This study maps outline Central Tianshan using Landsat images from four periods, i.e., 1989, 2002, 2007 and 2015, by an object-based classification approach, analyzes 2D 3D changes related to factors based Advanced Spaceborne Thermal Emission Reflection Radiometer (ASTER) Global DEM data. approach shows accuracy of 90.8% for clean ice mapping. The derived outlines are good agreement with 2nd Chinese Glacier Inventory (CGI2) Land Ice Measurements Space (GLIMS). fields northern aspect receive least solar radiation, leading dominant existing glaciers. Glaciers near evenly distributed slope zones 0° 50° mean angle 28.8°, resulting 30.3% larger 2015 Tianshan. decreased 404 km2 (−8.1%) between 1989 while declined 516 (−7.9%). showed reduction −1.8% −3.8% 2002 2007, −2.7% these retreating rates closely responded variations regional air temperature precipitation. Topographically, most reductions occurred elevation bands 3000–4000 m 10–20° 40–50°, eastern fields. Tekes River catchment had largest shrinking rate −17.0% area), followed southern Karasu (−14.2%) Muzart (−7.7%) catchments. In contrast, glaciers Kumerik/Aksu Tailan catchments Tuomuer region little change (−2%).