洪泽湖近50a特征水位变化规律及影响因素

Characteristic Water Levels of Hongze Lake in the Past Five Decades:Variation Rules and Influencing Factors

根据1967—2016年蒋坝、尚咀、高良涧和老子山4个水位站逐日数据,运用Mann-Kendall检验、有序聚类分析、BFAST算法和小波分析,揭示了洪泽湖特征水位年际、年内变化规律;并通过分别构建各特征水位与同期各入湖、出湖流量及降水量、蒸发量之间的多元回归关系,揭示了驱动洪泽湖特征水位变化的主导因素。研究表明:3类特征水位(平均水位、最高水位、最低水位)显著突变时期均在1982—1985年之间,1986年后洪泽湖特征水位呈显著上升趋势,最低水位变化响应时间最早,最高水位响应时间最晚;各特征水位均存在36、17、9 a的第1、第2、第3主周期;在蓄水期(Stage1)小柳巷入湖流量是影响平均水位和最低水位变化的主要因素,分别达到36%和33%,三河闸出湖流量是影响最高水位变化的主要因素,达36%;泄水期(Stage2)双沟入湖流量对最低水位影响更加明显,达到47%;涨水期(Stage3)小柳巷入湖流量在平均水位变化中起主要作用,达到29%。研究结果对于进一步认识洪泽湖水位变化规律具有重要意义,可为洪泽湖水位及上下游径流调控提供科学依据。

According to the daily water level data at Jiangba,Shangju,Gaoliangjian,and Laozishan stations from 1967-2016,we investigated into the interannual and annual variation rules of characteristic(average,maximum,and minimum)water levels in Hongze Lake via Mann-Kendall test,order cluster analysis,BFAST(Breaks for Additive Seasonal and Trend)algorithm,and wavelet analysis.Moreover,we revealed the dominant factor triggering the variation of characteristic water levels by constructing the multiple regression equation among each characteristic value and inflow and discharge,as well as precipitation and evaporation in the same period.1)The characteristic water levels experienced abrupt changes in 1982-1985.After 1986,the characteristic water levels witnessed a marked increase;the lowest water level responded the earliest,while the highest water level responded the latest.2)The fluctuation of characteristic water levels in Hongze Lake is highly consistent,with 36 years,17 years,and 9 years as the first,second,and third principal periods,respectively.3)In storage stage(stage 1,from October to next April),the flow rate at Xiaoliuxiang is the major factor that affect the average water level and minimum water level,accounting for 36%and 33%of the total impact factors,respectively;the flow rate at Sanhezha is the dominant factor for the highest water level,accounting for 36%.In discharging stage(stage 2,May to June),the flow rate at Shuanggou exerts a more evident impact on the lowest water level,occupying 47%of the total impact factors.In water-rising stage(stage 3,July to September),the flow rate at Xiaoliuxiang plays a prevailing role(29%)in average water level.The research results offer scientific basis for the regulation of water level and upstream and downstream runoff in Hongze Lake.