1959-2009年乌鲁木齐河源1号冰川零平衡线高度变化研究

基于1959-2009年间天山乌鲁木齐河源1号冰川观测资料,研究了该冰川零平衡线高度变化特征,并建立了零平衡线高度与夏季气温和夏季降水量之间的统计关系。研究表明:近51年来,1号冰川零平衡线高度呈缓慢上升、缓慢下降、急剧上升、急剧下降的变化趋势,但总体呈上升趋势,且该冰川零平衡线高度上升了约45m。1号冰川零平衡线高度和年净物质平衡有良好的线性关系,冰川处于稳定状态时的零平衡线高度为4018m。此外,对1号冰川零平衡线高度的气候敏感性研究表明,如果夏季气温升高(或降低)1℃,那么该冰川零平衡线高度将上升(或下降)约64m;如果夏季降水量增加(或减少)100mm,那么该冰川零平衡线高度将下降(上升)约21m,夏季气温是影响冰川零平衡线高度变化的主要气候因素。

Variations on equilibrium line altitude of the Glacier No.1 at the headwaters of Urumqi River,during 1959-2009

Based on the observation data of the Glacier No.1 at the headwaters of Urumqi River,Tianshan Mountains during the period 1959-2009,the variation characteristics of the equilibrium line altitude(ELA) were analyzed.Furthermore,statistical relations between ELA and summer air temperature and summer precipitation,which are the major influencing factors of ELA,were established.Results indicated that the ELA rose slowly and fell steadily,and then roses and declined sharply during the the past 51 years.However,the ELA of the glacier showed an increased tendency with the value of about 45 m for the entire period.Good linear correlation was existed between the ELA and annual net mass balance.The altitude of the equilibrium line was 4018m when the glacier was at the steady state.In addition,climatic sensitivity research of the altitude of the equilibrium line showed that the ELA ascended or descended by 64m when summer temperature increased or decreased by 1°C,and ELA ascended or descended by 21m when summer precipitation decreased or increased by 100mm.The summer air temperature was the leading climatic factor influencing the variations of ELA.