Mass balance variation of continental glacier and temperate glacier and their response to climate change in western China: Taking Urumqi Glacier No. 1 and Parlung No. 94 Glacier as examples
为认识全球变暖背景下中国西部大陆性冰川与海洋性冰川物质平衡变化及其对气候响应,以天山乌鲁木齐河源1号冰川和藏东南帕隆94号冰川为例,结合大西沟与察隅站气象资料,对19802015年两条冰川的物质平衡变化特征及差异进行了分析。结果表明: 36 a来乌源1号冰川与帕隆94号冰川物质平衡总体上均呈下降趋势,累积物质平衡达- 17 102 mm w. e.与- 8 159 mm w. e. ,相当于冰川厚度减薄19 m与9. 01 m,且分别于1996、2004年左右发生突变。同期两条冰川所处区域年均温呈显著上升趋势,而降水量却表现出不同的变化态势;二者年内气温分配相仿,但降水分配差异较大。初步分析认为气温上升是导致乌源1号冰川与帕隆94号冰川物质亏损的主要原因,冰川区气温和降水变化幅度的差异和地性因子(坡度、冰川面积)的不同使得乌源1号冰川对气候变化响应的敏感性高于帕隆94号冰川,由于目前海洋性冰川物质平衡监测时段相对较短,为深入研究中国西部冰川物质平衡变化及过程仍需加强对冰川的持续观测。
英文摘要:
Glacier mass balance is a key parameter for monitoring strategies of the earth climate system,due to its direct and undelayed response to local atmospheric conditions. Considering the reliability of mass balance observation and data quality,Urumqi Glacier No. 1 (UG1) in the Tianshan Mountains and Parlung No. 94 Glacier (PG94) in the Gangrigabu Range are selected as the reference glacier of continental glacier in northwest arid region and temperate glacier in southeast Tibetan Plateau of China, respectively. Thus, it is reasonable to take UG1 and PG94 as sample glaciers to indicate the mass balance fluctuation for continental glacier and temperate glacier and their response to climate change in western China. Combined with meteorological data of Daxigou and Zayu station,glacier mass balance variation and discrepancy for UG1 and PG94 from 1980 to 2015 are analyzed. The results indicated that the annual mass balance for UG1 and PG94 show a decreasing trend by - 15. 70 (P < 0. 01) and - 35. 15 mm w. e. a ~(- 1) (P < 0. 001) , respectively. The cumulative mass balance for UG1 and PG94 are found to be - 17 102 and - 8 159 mm w. e. in 36 years,equivalent to ice thickness reduced by 19 m and 9. 01 m. Their mutation points occurred in 1996 and 2004 at the 0. 05 level, respectively. The annual mean temperature for UG1 and PG94 show a significant increasing trend by 0. 5 ℃·(10 a) ~(- 1) and 0. 3 ℃·(10 a) ~(- 1),(P < 0. 001) respectively over the study period. And their mutation points occurred in 1996 and 2000 at the 0. 05 level, respectively. The annual precipitation for UG1 and PG94 show a different trend in 36 years,an increasing trend [34 mm ·(10 a) ~(- 1),P < 0. 05]is found for UG1,while PG94 exhibits a decreasing trend [- 57 mm ·(10 a) ~(- 1)]. The mutation point of annual precipitation occurred in 1988 for UG1,while for PG94 it was in 1982 and 2009 at the 0. 05 level. The inner - annual distribution of air temperature for UG1 and PG94 are almost similar,but inner - annual precipitation distribution is different in two glacial regions. There were 66% of annual precipitation concentrated in summer period for UG1, while spring and summer precipitation accounted for 38% and 37% of the annual precipitation in PG94, respectively. The correlation analysis between glacier mass balance and temperature and precipitation of UG1 and PG94 show that mass balance are more closely with temperature in term of precipitation,especially for summer temperature. The response of glacier mass balance is not only affected by the regional climate conditions,but also depends on the topographic conditions. It is higher in UG1 than that of PG94 owing to the increase of annual mean and summer temperature of UG1 in the past 36 years. Furthermore,UG1 has larger slopes and smaller area than PG94,making the UG1 more sensitive to the recent climate warming. Considering the monitoring history of temperate glacier mass balance is relatively short, it is still necessary to strengthen glacier mass balance observation,which could provide a scientific data to understand the changes and processes of glacier mass balance in western China.