基于变带宽核密度估计的鄱阳湖生态水位研究

摘要

鄱阳湖流域水文过程在气候变化与人类活动共同影响下产生显著变异，湖泊生态系统适应了变异前出现频率较高的水文条件。采用多种变异诊断法对湖泊水位进行综合变异检测，采用变带宽核密度估计法对变异前日水位序列进行拟合，取概率密度最大处水位作为生态水位。研究结果表明：①鄱阳湖水位于1979年发生弱变异，变异后湖泊平均水位上升0．5 m；②变带宽核密度估计是用于研究鄱阳湖变异前水位序列概率密度最大处水位的最佳统计方法。③变异后，5－6月份生态水位满足率显著减小，平均生态水位满足率不足50％。本文研究成果可为鄱阳湖生态保育、水生态与水环境保护及水资源管理提供科学依据。%Hydrological processes of the Poyang Lake are significantly altered under the influences of hu-man activities and climate changes.Ecological system has aological alterations indapted to the hydrologi-cal conditions before hydrological alterations in the Poyang Lake.Given this,we use various kinds of al-terations diagnosis methods to test the lake water level.Then we use variable bandwidth kernel density estimation to fit respectively daily water level for each month before hydrological variations.We regard largest probability of water level as the ecological-level the Poyang Lake.The following results were ob-tained:① The variation of water level in the Poyang Lake occured in 1 979,with the increase of 0.5 me-ter in the mean water level.② Variable bandwidth kernel density estimation is the best statistical method for studying of maximize density water level before hydrological alterations in the Poyang Lake.③ After the hydrological variation,the fill rate of ecological-level reduced significantly.with an average value of ecological-level fill rate less than 50%.Runoff changes are the major factors influencing the ecological-level fill rate;Water conservancy projects and forest coverage can help to improve the low-flow,so the ecological-level fill would increased significantly in dry seasons after alterations.This research results will provide important scientific basis for the ecological conservation,water ecology and water management within in the Poyang Lake basin in a changing environment.