近十年可可西里盐湖水量变化及其影响因素分析

Analysis on water volume changes and influencing factors of 68 Daoban Salt Lake in Hoh Xil in recent ten years

由于全球气候变暖的影响,青藏高原湖泊开始逐步扩张,对自然环境和野外基础设施产生了威胁。为研究气候变化对湖泊水量的影响,利用2010~2018年青海可可西里腹地盐湖(又名68道班盐湖)的CryoSat-2卫星测高数据和Landsat遥感影像数据,分别提取了盐湖的水位及面积,结合实测获取的盐湖水下地形数据,计算并构建库容关系曲线,并结合气候变化特征进行了驱动力分析。结果表明:(1)2010~2011年,湖泊水量增加了0.2亿m^(3),这一阶段盐湖还是独立湖泊;之后上游卓乃湖、库赛湖、海丁诺尔湖3个湖泊的湖水开始注入盐湖,盐湖成为流域水量“接收者”,水量开始快速增加,仅1 a就暴涨近12亿m;(该阶段主要为上游3个湖泊溢出水量);2016年开始以平均每年约5.5亿m;的速度上涨;9 a间,盐湖的水量增加近33亿m^(3),并且作为流域水量的“接收者”,盐湖还在持续扩张。(2)降水量增加是盐湖扩张的主要因素,温度上升引起的冰川融化和冻土融水是湖泊变化的另一气候因素,但可能不是决定性因素。

Due to the impact of global warming,lakes on the Qinghai-Tibet Plateau have begun to gradually expand,posing a threat to the natural environment and field infrastructure.In order to study the impact of climate change on lake water volume,based on CryoSat-2 satellite altimetry data and Landsat remote sensing image data of the 68 Daoban Salt Lake(Salt Lake)in the hinterland of Hoh Xil,Qinghai Province from 2010 to 2018,we extracted the water level and area of the Salt Lake respectively,and combined with the measured underwater topographic data to construct a water level-area-volume relationship curve.Based on the characteristics of climate change,we analyze the driving force of Salt Lake variation.The results showed that:(1)from 2010 to 2011,the water volume of the lake increased by 20 million cubic meters,and the Salt Lake was still an independent lake at this stage.After that,the water from the three upstream lakes,Zhuonai Lake,Kusai Lake and Haidingnuoer Lake began to inject into the Salt Lake,then the Salt Lake became the"receiver"of water in the basin,and the water volume began to increase rapidly,rising by nearly 1.2 billion cubic meters in just one year.In 2016,the water volume started to rise at an average rate of about 550 million cubic meters per year.In the past 9 years,the water volume of Salt Lake increased by nearly 3.3 billion cubic meters,and as the"receiver"of water in the basin,Salt Lake continued to expand.(2)Increasing rainfall is the main factors for the expansion of the Salt Lake.Melting glaciers and permafrost meltwater caused by increasing temperature may be another climatic factor for lake changes,but not the decisive one.