慕士塔格冰芯降水记录及其对冰川水资源的气候意义

2003年在东帕米尔慕士塔格冰川海拔7010 m处钻取了的一支长41.6 m的冰芯,从中恢复了1955年以来的积累量.结果表明:自20世纪70年代以来,冰川积累量持续减少,特别近年来积累量呈加速减小趋势;平均而言,20世纪90年代后期至2003年平均积累量只有20世纪60年代冰川积累量的一半.重建的慕士塔格地区冰川物质平衡近20 a来亏损严重,主要是由近年来慕士塔格高山区降水的减小和温度的升高共同作用引起的.对主要以冰川融水为补给的塔里木河流域上游山区而言,短期冰川融水的增加会调节河流径流,而当冰川得不到足够的降水补充时,冰川的退化必然影响到下游的河流径流.

Records of Precipitation in the Muztag Ata Ice Core and Its Climate Significance to Glacier Water Resources

During the summer 2003,a 41-m firn and ice core was extracted at the elevation of 7 010 m above sea level to determine annual accumulation rates at Muztag Ata Peak in the East Pamirs.Using strong seasonally variation of oxygen isotopic of the core to define annual layers,a 45-year record is obtained.Annual snow accumulation over the period is about 0.62 m water equivalent on average.The snow accumulation was higher during 1958-1975 than during 1976-2003.The accumulation decreased by a factor of two to three between 1958 and 2003.The reconstruction of mass balance in Muztag Ata glacier by using snow accumulation and temperature show a dramatically increasing wastage tendency in the past 20 years.The mean mass balance in Muztag Ata glacier was -123 mm·a^-1 during the period of 1960-2003,while it reached to -419 mm·a^-1 in the period of 1990-2003.Both the decreasing in snow accumulation at the high mountain and the increasing temperature are responsible for the wastage of glacier in Muztag Ata region.The increment of glacier wastage can enhance runoff of the Tarim River fed by glacier melting water in a short period.However,in the condition of global warming the glacier without enough supplements will shrink quickly.For a long period,most of the snow and ice will be gone and the Tarim River runoff will be reduced without glacier melting water fed.