天山乌鲁木齐河源1号冰川径流对气候变化的响应分析

Response of Runoff to Climate Change in the Glacier No.1 at the Headwater of rümqi River,Tianshan Mountains during 1980—2006

利用天山乌鲁木齐河源1号冰川1959—2006年的气象、冰川物质平衡和1980—2006年的水文资料,分析了其冰川径流的变化.结果表明:由于1996年以来的显著升温,导致了1号冰川水文点径流主要受夏季气温变化的控制,冰川物质损失对径流的补给作用已超过了降水的作用.1996—2006年与1980—1995年相比,夏季气温升高了0.9℃,降水增加了84.8mm(18.1%),冰川径流增加256.6mm(37.3%),其中约12.3%来自降水增加,约26.9%来自冰川物质的加速消融.对1980—1995年和1996—2006年两个时间段的气温和径流变化进行比较,并考虑到冰川区降水主要为降雪,折合夏季气温升高1℃将导致冰川径流增加470mm.夏季气温与冰川物质平衡和冰川径流的统计分析亦得出同样的结果.

Response of glacier runoff to climate warming in the past 27 a was analyzed using precipitation,glacier mass balance and discharge measured in the Glacier No.1 at the headwater of the ürümqi River,Tianshan mountains.Summer air temperature increased by 0.20 ℃·（10a）-1 during 1959—2006,with a pronounced increase（0.9 ℃） in the period of 1996—2006,as compared with the period of 1980—1995.Pearson correlation coefficient between annual discharge and summer air temperature was higher after 1995 than that before 1995.Distinct climate warming led to 349.2 mm decrease in glacier mass balance from the period of 1980—1995 to the period of 1996—2006,even though annual precipitation increased about 84.8 mm（18.1%）.As a result,annual runoff in the basin increased 37.3%,of which 12.3% was due to precipitation increase and 26.9% was due to glacier mass loss.1.0℃ increase in summer air temperature would result in about 486 mm increase glacier mass loss,and 470 mm increase in glacier runoff or 104% increase of glacier runoff in glacier stable condition.Same results can be seen in the analyses of basin water balance,relationship between summer air temperature and glacier mass balance and annual runoff.