1976-2015年柴达木盆地湖泊演变及其对气候变化和人类活动的响应

Lake evolution in the Qaidam Basin during 1976-2015 and their changes in response to climate and anthropogenic factors

柴达木盆地众多的湖泊不仅对维持当地脆弱的生态环境具有极其重要的作用,而且中心盐湖也是重要的矿产资源.进入21世纪以来,受气候变化和人类活动的共同影响,盆地湖泊发生了一系列重大变化.为科学认识这一问题,选取了1976-2015年6期Landsat系列卫星影像,解译了该区域1 km2以上的湖泊水面,并分析了湖泊变化对气候和人类活动的响应.结果表明:柴达木盆地湖泊面积总体上存在扩张(1976-1990年)-萎缩(1990-2000年)-扩张(2000-2010年)-萎缩(2010-2015年)4个阶段的变化过程,2010年湖泊面积最大,2015年湖泊又明显萎缩.就气候水文因素而言,湖泊面积变化主要受山区降水径流的影响.湖面变化与前3 a的降水径流关系最为密切.进入21世纪以来,气候变化与上游社会经济耗水、盐湖周边人为阻隔河湖连通、开采卤水、修建人工盐田、排放老卤等人类活动,对盆地中心湖泊的空间格局、面积都产生了显著影响,苦水沟、达布逊湖南部形成了新湖泊,鸦湖、团结湖面积显著扩大,东、西台吉乃尔湖逐渐萎缩、干涸,一里平湖由以前的干盐湖在2010年一跃成为盆地最大的湖泊.针对盐湖大规模开发产生的负面影响,提出了合理开发盐湖资源的建议.

Lakes in the Qaidam Basin play a critical role in maintaining the fragile ecological environment. Moreover,the salt lakes in this region are important mineral resource. Since the beginning of the 21 st century,lake area in this basin has changed drastically due to the driving of climate change and human activities. For further understanding lake evolution in this basin,lakes larger than 1 km2 between 1976 and 2015 are derived from Landsat data. The results show that lake area in the basin has experienced four evolution stages,i. e. extension in 1976-1990,shrinkage in 1990-2000,extension in 2000-2010,and shrinkage in 2010-2015. The largest lake area is appeared in 2010. In terms of climatic and hydrological factors,the precipitation and runoff are the dominant factors for lake area variations. The change of lake area is most closely related to the precipitation and runoff in the first 3 years. Since 2000,both climate change and human activities such as water consumption in the catchment,blocking rivers and lakes connection around the lake,brine mining utilization,constructions of solar ponds have significant influence on the spatial pattern and size of the central lakes of the basin. A new lake was formed at Kushui River and south of Lake Dabuxun,the areas of Lakes Ya and Tuanjie were significantly expanded,the East and West Lake Taijinar shrank and dried,and the Lake Yiliping expanded from a playa to the largest lake in the Qaidam Basin in 2010. In view of the negative influence of the large scale exploitation of saline lakes,this paper puts forward some suggestions for the rational development of saline lake resources.