Glaciological Studies in Asian Highland Regions

点击翻译按钮获取中文摘要

Glaciological studies in Asian highland regions in 1989-1990 were made in eastern Tibet and the Nepal Himalaya. Purposes of this project in Tibet were studies of characteristics of glaciers in different climates and the role of the cryosphere in meteorological and hydrological processes on the Tibetan Plateau. Field observations were carried out during the two periods, May-June and September-October, in the East Kunlun Mountains, Tanggula Mountains and Nyaingentanglha Mountains. Intensive observations of glaciology, meteorology and hydrology were carried out in the Tanggula Mountains.A purpose of this project in the Nepal Himalaya was continuous data collection at the hydrological and meteorological station in Langtang Himal which has been maintained since 1985. In addition, glacier fluctuations for over ten years were observed in the Khumbu, Shorong and Langtang regions.Preliminary results of the research are as follows,1. Main accumulation of glaciers in eastern Tibet in a year is supplied with summer precipitation. Continental-type glaciers on the plateau are located in regions with low precipitation, and formation of superimposed ice by refreezing of melt water is important for glacier mass balance in such dry area.2. Abundant snowfall on the Tibetan Plateau occurs partly due to large scale disturbance and partly due to strong local convection. Oxygen isotopes composition of precipitation shows a possibility of precipitation from local origin water vapor.3. Formation of snow cover on the Tibetan Plateau results in cooling of atmosphere and retardation of deepening of the permafrost active layer. Abundant evaporation was observed at the snow surface.4. Small glaciers in east Nepal have been retreating in distance of 30-50m since 1970s depending on air temperature variation.