REGIME AND MASS-ENERGY EXCHANGE OF SUBTROPICAL LATITUDE GLACIERS UNDER MONSOON CLIMATIC CONDITIONS - GONGGA-SHAN, SICHUAN, CHINA

The aim of this study is to explore the conditions that are conducive to the current glaciation at low latitudes in Central Asia. Various climatic conditions are examined as well as the nature of the monsoon and atmospheric circulation. It was established that the area is located in the zone influenced by both tropical monsoons and extropical cyclones. The quantitative development of the components of mass-energy exchange of the mountain environment and the Gongga Shan glacial system of western Sichuan is based upon fieldwork undertaken between 25 September and 22 November 1990. The glaciers exist mainly because of the climatic features associated with the monsoon circulation regime. Solar radiation intensity during the summer-autumn monsoon for the ablation area is one sixth of that theoretically possible for these latitudes. The major patterns of the glacial regime controlled by monsoons have been identified. At 5,000 m the impact of the summer monsoon on temperature distribution is reduced. Glacial melt in the study area takes place mainly from advection; this process of melting during the summer monsoon occurs both day and night. Precipitation increases with altitude up to 3,000-3,600 m. The area of current glaciation in the Gongga Shan massif is about 90 km2. At the present time the mass balance trend is negative; for the period 1989/90 it equaled -12 g cm-2.