近60 a伊塞克湖水量平衡变化及影响因素分析

Analysis of water balance change and influencing factors in Issyk-Kul Lake in recent 60 years

基于卫星遥感数据,提取近60 a伊塞克湖面积、水位变化信息,反演伊塞克湖水量变化时间序列,结合1960—2020年CRU气象数据、1960—2000年乔尔蓬阿塔气象站气温降水观测数据和入湖水量观测数据,建立湖泊水量平衡模型,分析水量平衡各分量的变化特征,并探讨其影响因素。结果表明:(1)1960年以来伊塞克湖水量变化经历了持续减少-波动增加的过程,1998年为变化的时间拐点;20世纪60—80年代中期,入湖水量主要受灌溉引水影响持续减少,1986年后随灌溉水量减少、降水和冰川融水的增加而转为上升趋势;湖区降水以9.1 mm·(10a)^(-1)的速率增加,蒸发量随湖区升温和湖体面积增加总体呈显著增加趋势。(2)20世纪80年代中期以前伊塞克湖大部分年份湖泊水量呈负平衡,地下水持续补给湖泊,1986年起湖泊的水量收支亏损逐渐减小,1998年以来以正平衡为主。(3)入湖径流、降水、蒸发等水量平衡分量的互动关系决定了湖泊水量的变化,而产流区气候变化和灌区灌溉引水通过改变入湖径流间接驱动湖泊水量的变化;1960—1986年,以灌溉引水为主的人类活动是驱动伊塞克湖水量变化的主导因素,贡献率达71.6%,1987年以来,气候变化因子对湖泊水量变化的累计贡献超过80%。

Based on the satellite data,the water level and area information of Lake Issyk-Kul was extracted,and the water volume was reconstruct;combined with CRU meteorological data from 1960-2020,the temperature and precipitation observation data from 1960-2000 at the Cholpon-Ata meteorological station and the water volume observation data into the lake,the lake water balance model was established to analyze the changing characteristics of each element of the water balance and to explore its influencing factors.The results indicated that:(1)Since 1960,the water volume of Issyk-Kul Lake has undergone a process of continuous decrease and fluctuating increase,with 1998 being the inflection point of the change;from the 1960s to the mid-1980s,the water volume into the lake decreased continuously mainly due to the influence of irrigation diversions,and then turned to an increasing trend after 1986 with the decrease of irrigation water and the increase of precipitation and glacial meltwater;precipitation in the lake area increased at a rate of 9.1 mm·(10a)^(-1),and the evapotranspiration tends to increase significantly with increasing temperature and lake area.(2)Before the mid-1980s,Issyk-Kul had a negative water balance in most years,and groundwater continued to recharge the lake;since 1986,the water balance deficit of the lake gradually decreased,and since 1998,the positive balance has been dominated.(3)The interaction of water balance components such as runoff,precipitation and evaporation determines the changes in lake water volume,while climate change in the flow-producing areas and irrigation diversions in irrigation areas indirectly drive the changes in lake water volume by changing runoff;from 1960 to 1986,human activities,mainly irrigation diversions,were the dominant factor driving the changes in Issyk-Kul water volume,with a contribution of 71.6%,and since 1987 the cumulative contribution of climate change factors to changes in lake water volume exceeds 80%.