湖泊的水位数据作为评价湖泊变化的重要指标,对于研究区域水资源变化和生态环境状况具有重要意义。但绝大多数高原湖泊位于人烟稀少、自然条件恶劣的高海拔地区,往往难以获取基础观测数据。以卫星测高数据和遥感影像数据为基础,获得2008—2018年库赛湖水位和面积数据,并结合气象数据对水位变化原因进行分析。结果表明:库赛湖水位变化先后主要经历了缓慢上涨(2008—2011年)→急剧上涨(2011年)→趋于稳定(2013—2018年) 3个阶段。2008—2011年是湖泊水位的缓慢上升期,气候暖湿化是主要原因;2011年由于上游卓乃湖发生溢流,水位短时间内急剧上涨;2012—2018年,在接收大量来水后库赛湖也发生外溢,与上下游湖泊串联成一体,水位开始趋于稳定。对水位数据和气象特征因子进行相关性分析,可见湖泊水位与气象因子的变化情况具有较好的相关性,初步分析认为区域降水量增加是库赛湖水位上涨的主要原因,而气候变暖引起的冰川融水增加、冻土水分释放可能是次要原因。

The water level data of lakes, as an important indicator for evaluating changes in lakes, are of great significance for studying regional water resources changes and ecological environment conditions. However, most of the plateau lakes are located at high altitudes where population are sparse and natural conditions are harsh, and it is often difficult to obtain basic observation data. Based on satellite altimetry data and remote sensing image data, we obtained the water level and area data of Kusai Lake from 2008 to 2018, and analyzed the causes of water level change in association with meteorological data. Results manifested that the water level of Kusai Lake had gone through three stages from slow rise (2008-2011) to sharp rise (2011), and then to stabilization (2012-2018). The slow rise in the 2008-2011 stage was mainly triggered by warming and humidification of climate; the sharp rise stage in 2011 was caused by overflow in the upstream of Zhuonai Lake; in the 2012-2018 stage, the water level began to stabilize due to overflow in the Kusai Lake after receiving a large amount of incoming water and hence integrating with the upstream and downstream lakes in series. Correlation analysis of water level data and meteorological characteristic factors showed good correlation between lake level and changes in meteorological factors, and preliminary analysis suggested that the increase in regional precipitation was the main reason for the rise in water level of Kusai Lake, while the increase in glacial meltwater and permafrost moisture release caused by climate warming might be secondary causes.