Abstract:  Many researches have shown that most glaciers in the world experienced a general reduction in area due to climate warming in recent decades. The glaciers in headwaters of the Yangtze River in the central-northeast part of Qinghai-Tibetan Plateau are mainly distributed in the north-oriented slopes of Mt. Tanggula and Mt. Sedir and the south-oriented slopes of Mt. Kunlun. In this study, the change of glaciers in the whole headwaters was monitored using the 1∶100 000 topographic maps based on the aerial photographs taken in 1969/1971 and the Landsat ETM+ imageries in 1999/2002. Moreover, Landsat MSS (1973), Landsat TM (1992) and 2 scenes 2005 and 2006, ASTER images at level 1B, were used to study the change of glaciers in the Geladandong Peak area in multi-periods. It was found that the most glaciers in the headwaters were in a retreat. In general, the glaciers were retreated by 108.3 m in average, and an area of 68.13 km² was lost, accounting for 5.3% of the total glacier area. There was a significant difference in glacier change rate among the Mt. Tanggula, Mt. Sedir and Mt. Kunlun. Shrinkage of area of the glaciers was 12.9% in the Mt. Sedir, 4.3% in the Mt. Tanggula, and 8.3% in the Mt. Kunlun respectively. The results of glacier change in the Geladandong Peak area in multi-periods showed that the reduction of glacier area was the most significant during 1969-1973, about -1.16 km²·a^-1, and the glacier area was enlarged by 0.59 km²·a^-1during 1973-2002. However, the reduction of glacier area was accelerated after 2002 with a change rate of -0.95 km²·a^-1. Generally, the larger the glacier area was, the lower the glacier change rate would be. According to the statistic analysis, there was a decreasing logarithm relationship (R²=0.91)between the glacier area and the area reduction rate in the study area. The meteorological data observed by Zhiduo, Tuotuohe and Wudaoliang Glacier meteorological stations revealed that the retreat of glaciers in this area may be mainly caused by the increase of air temperature in warm season, and the different extent of temperature increase may be one of the reasons resulting in the different glacier change rate among the Mts. Tanggula, Mt. Sedir and Mt. Kunlun.

Key words: