基于ICESat/GLAS数据的可可西里地区湖泊水位变化研究

STUDY ON MONITORING LAKE WATER LEVEL CHANGES IN THE HOH XIL REGION BASED ON ICESAT/GLAS DATA

[目的]湖泊水位数据是湖泊水量平衡的重要指标,也是湖泊溃决模拟研究的重要参数,通过研究,获得可可西里地区主要湖泊水位数据及其变化过程,对认识藏北地区水资源变化及突发湖泊溃决洪水具有重要意义。[方法]以文献资料、湖泊矢量数据、2003—2009年ICESat/GLAS卫星测高数据为基础获得1993—2009年可可西里地区主要湖泊水位数据,并结合气象等数据对湖泊水位变化原因进行了分析。[结果](1) 1993—2009年可可西里地区湖泊水位整体上呈上升趋势,水位下降的湖泊数量较少,但呈现出一定的区域差异,其中错尼湖泊水位上升了24. 68m,银波湖下降了6. 16m;有7个湖泊水位波动幅度在10～15m之间,应该引起人们重点关注。(2)可可西里地区湖泊水位动态变化主要与气候变化有关,其中降水增加(或减少)和湖面蒸发减少(或增加)是导致湖泊水位上升(或下降)的决定性因素,而气候变暖引起的冰川融水增加、冻土水分释放以及区内地下水补给形式可能是次要原因。[结论]利用卫星遥测技术对大范围无人区湖泊水位信息提取优势明显,数据时间序列较短是其瓶颈。可可西里地区湖泊数量众多,湖泊水资源调查和水安全评估应予以重视。

Lake level data is an essential indicator for calculating lake water balance,and is also a significant parameter for lake break simulation research. Obtaining the data of the main lake water level and its changing process in the Hoh Xil area are of great significance to the assessment of water resources and flood disaster monitoring in the local and even the whole country. Literature investigation,lake vector data and ICESat/GLAS satellite altimetry data from 2003 to 2009 were used to extract lake level data of major lakes in the Hoh Xil region from1993 to 2009 combining with the meteorological and other data were also integrated to analyze causes of lake level variation. The results showed that( 1) On the whole,from 1993 to 2009,the lake level in the Hoh Xil region presented a rising tendency,and less numbers of lakes declined the water level,however it also showed certain regional difference.CoNyi Lake expanded by 24. 68 m,and Yinbo Lake dropped 6. 16 m in water level;water level of 7 lakes fluctuated in the range of 10 ~ 15 m,which should been seriously noticed.( 2) The dynamic change of lake water level in the Hoh Xil area was mainly related to climate change. Increased( or reduced) precipitation and reduced( or increased) evaporation of the lake were the decisive factors that caused to rise( or descend) of lake water level. And the secondary factors were the increase in frozen soil due to climate warming,melt water from glaciers and groundwater recharge form in the region. The using of satellite remote sensing technology for extracting lake water level information in large-area uninhabited areas has obvious advantages,but which has bottleneck of shorter time series of data is its bottleneck. Large number of lakes distribute in the Hoh Xil area,so lake water resources surveys and water safety assessments should be taken seriously.