帕隆藏布流域(波密-然乌段)冰川动态变化遥感分析

Remote Sensing Analysis of Glacier Dynamic Changes in Parlung Zangbo River

帕隆藏布流域位于中国海洋性冰川最为发育的藏东南地区,近年来随着全球温室效应加剧,帕隆藏布流域冰川变化极为显著。采用多期遥感影像,对1994~2015年间帕隆藏布流域波密至然乌段的冰川变化趋势、原因及其影响进行研究。结果表明:①20余年间冰川总面积减少了451.72 km 2,各冰川每年大约退缩2.48%~2.95%,气温升高以及降雨量减少是导致冰川面积持续退缩的主要原因。②由于帕隆藏布江南岸山坡所接收的太阳辐射热量更少,但降水却更加充沛,使得帕隆藏布江南岸冰川分布面积及覆盖率远大于北岸,而冰川退缩速率远小于北岸。③冰川的不断退缩使得沟道上游大量冻融松散物源在冰雪融水的外动力条件下,进入沟道形成松散堆积物源,导致流域内大规模发育冰川泥石流。由于帕隆藏布江南岸冰川规模更大,导致帕隆藏布江南岸冰川泥石流更为发育。④冰川变化动态监测对冰川泥石流机理分析以及预警研究工作有着重要的参考指导价值。

Palong Zangbo Basin is located in southeastern Tibet where maritime glaciers are most developed in China.In recent years,with the intensification of global greenhouse effect,the glacier changes in Palong Zangbo Basin are very significant.The trend,causes and effects of glacier changes in the Palong Zangbo Basin(the section of Bomi and Ranwu) from 1994~2015 are studied by using multi temporal remote sensing images.The results show these as follows.① Over the past 20 years,the total area of glaciers in the study area has decreased by 451.72 km 2,and each glacier retreats by 2.48%~2.95% annually,the increase of temperature and the decrease of rainfall are the main reasons for the continued retreat of glacier area.② The southern slope of the Palongzangbo River receives less solar radiation heat,but the precipitation is more abundant,making the glacier area on the southern bank of the Palongzangbo River much larger than that on the northern bank,and the retreat rate of glaciers on the south bank is much lower.③ With the continuous retreat of glaciers,a large number of frozen and thawed loose material sources in the upper reaches of the gully enter the gully under the external dynamic conditions of ice and snow melting water to provide material sources,resulting in large-scale development of glacial debris flows in the Palong Zangbo Basin.Glacier debris flows on the southern bank of the Palong Zangbo River are more developed because of the larger scale of the glaciers.④ Strengthening dynamic monitoring of glacier change has important reference and guidance value for mechanism analysis and early warning research of glacier debris flow.