天山南坡台兰河流域冰川物质平衡变化及其对径流的影响

Glacier Mass Balance Change in Tailanhe River Watersheds on the South Slope of the Tianshan Mountains and Its Impact on Water Resources

应用控制流域的径流及相关降水资料 ,通过模型重建了台兰河流域平均冰川物质平衡序列 .结果显示 ,195 7— 2 0 0 0年流域冰川平均年物质平衡为 - 2 87mm ,累计冰川物质平衡 - 12 .6m ;4 4a来由于气温升温引起的冰川净消融相当于每年补给河流径流 1.2 4× 10 8m3 ,占河流年径流量的 15 % .1982年以后 ,流域冰川物质平衡一直呈负平衡 ,195 7— 1981年平均物质平衡为 - 16 8mm·a-1,1982—2 0 0 0年平均为 - 4 4 5mm·a-1.随着气候由暖干向暖湿转型 ,降水量增加 ,但冰川对气温的敏感性更大 ,冰川消融加快 ,冰川融水量持续增加 .气温和降水量的变化与北大西洋涛动和北极涛动变化一致 ,其突变年份都在 1986— 1988年左右 .

The Tarim Basin is the biggest arid inland basin in China, it is located in Asia European Continent and far away from the sea. Tailanhe Watershed is located on the southern slope of the highest peak, Tumer, 7435.3 m asl, of the Tianshan Mountains, source from the Jong Tailan Glacier, inflow to the Tarim Basin, southern Xinjiang. The area of the watershed controlled by the Tailan Hydrological Station is 1 324 km 2 , the existing glaciers cover 431 km 2 in area and 32.6% of the total watershed area. Precipitation increases with altitude, mean annual rainfall is about 683 mm, the maximum rainfall appears on glacial cover area with 1 329 mm depth. Mean annual streamflow of 1957-2000 is 7.5×10 8 m 3 in the watershed, with 566 mm in average water depth. The climate is controlled by the westerly stream and air mass from Northern Atlantic Ocean and Artic Ocean pass through centre Asia and Europe, the warm season is the main glacier replenishment period. Major climatic features are a spring-summer precipitation maximum occurring simultaneously with ice and snow melt. Over the past decades years, the Tianshanin have started melting down with the increase in temperature leading to increasing glacier fed streamflow. The glacial runoff is 65% of average annual runoff in the Tailanhe watershed, mean annual glacier mass balance in 1957-2000 is -287 mm per year and total 44 years ice mass loss 12.6 m in thickness. 1982 is a key year, a dominating weaker positive mass balance character shift to strong negative phase, and mean annual mass balance changed from -168 mm per year in 1957-1981 to -445 mm per year in 1982-2000. A sensitivity test shows that 1 ℃ annual air temperature change will cause 300mm glacier mass balance fluctuation, and 16% amplitude of average annual runoff. As global warming, the glacier melts strengthening and meltwater increasing rapidly, more water resources supply to arid Tarim Basin. In the Xinjiang area, the climate is affected mostly by the westerly current coming from the Atlantic Ocean and the Arctic Ocean. The Northern Atlantic Oscillation and the Arctic Oscillation indices affect the precipitation, temperature and glacier mass balance variations of the Tianshan Mountains. The climate shift in northwest China is linkage to NAO/AO strength change, a reason of the causes.