Mass balance of Nyainqen Tanglha glacier, Tibet, 1977 to 2001, derived by topographical maps and satellite images

Abstract

NyainQen TangLha Glacier plays an important role in the Tibetan plateau’s climate system. Because of high altitude, steeply sloping terrain and difficult access, regular, systematic surveys of glacial variation are almost impossible in most regions of the glacier. As a result, satellite images are a convenient tool for studying the mass balance of the glacier, allowing us to conduct research over steep and otherwise inaccessible areas. This paper studies the mass balance of the NyainQen TangLha glacier area (30°15'N, 90°10'E, 5000-7000 m a.s.l. some 100 km to north-west of Lhasa.) in the Tibet Autonomous Region during the last few decades and investigates possible future glacial variations due to climate change. The aim is to examine variations in the terminus of different glacial tongues of the main glacier. The study is based on a comparison between an original topographic map produced in the earlier USSR in 1977 and satellite images from band 9 of ASTER in November 2001. Examining these two sources shows a negative change in the mass balance of all glacial tongues in the region. This study discusses the reasons for this with respect to changes in ablation, in accumulation