西藏玛旁雍错流域冰川与湖泊变化及其对气候变化的响应

利用遥感和地理信息系统技术,基于1974,1990,1999和2003年4个不同时期的遥感影像,包括Landsat系列影像,ASTER影像和地形图,研究了玛旁雍错流域(面积7786 km²)内冰川与湖泊的变化及其对气候变化的响应。研究结果表明,由于气候变暖,在过去30年里该流域冰川和湖泊都以退为主,有进有退。自1974年到2003年,冰川面积从107.92 km²减少到100.39 km²,冰川退缩明显加速。由于年降水量减少、蒸发量增大,30年中湖泊总面积从782.24 km²减少到748.08 km²。湖面的缩小与扩涨都在加速,尤其是小湖泊变化更明显,湖泊的加速变化可能是青藏高原高海拔内陆流域水循环过程加速的表征之一。

Glacier and lake co-variations and their responses to climate change in the Mapam Yumco Basin on Tibet

Glacier and lake variations in the Mapam Yumco Basin were studied by integrating series of spatial data from topographic maps and Landsat images in four different periods of time:1974,1990,1999 and 2003.The results indicate that glaciers and lakes in the Basin both retreated and advanced during the last 30 years.As a contribution to the studies of the impact of climate change on glaciers and lakes in high-altitude closed basins of the western Himalayas,we present spatial and temporal variations of glaciers and lakes in the Mapam Yumco Basin on the Tibetan Plateau,by means of Geographical Information System and Remote Sensing techniques.Our results show that both glacier and lake areas in the Mapam Yumco Basin decreased from 1974 to 2003.Glaciers in the basin have receded due to the warmer climate,in total by 7.53 km2(0.26 km2 a-1 or 0.25 % a-1)during 1974 2003(c.f.0.07 % a-1 nearby the Yamzhog Yumco Basin,and 0.18% a-1,the mean glacier recession rate over China since the 1960s).During the same period,lake area decreased by 34.16 km2(1.18 km2 a-1 or 4.37 % of whole lake area in the basin)in total,where decreased by 1.43 km2 a-1 on average(with lake shrinkage amounting to 1.70 km2 a-1 in some areas and lake growth to 0.27 km2 a-1 in others)during 1974-1990,by 1.55 km2 a-1(with lake shrinkage amounting to 2.15 km2 a-1 in some areas and lake growth to 0.60 km2 a-1 in others)during 1990-1999,while enlarged by 0.66 km2 a-1(with lake shrinkage amounting to 2.24 km2 a-1 and lake growth to 2.89 km2 a-1)during 1999-2003 over the past three decades.It is suggested that both enlargement and reduction of lakes were accelerated,which might be an indicator for an accelerated water cycle process over the Tibetan Plateau in a warming climate condition.