摘要
水文情势是水生态环境质量的重要参考依据,研究湖泊、河流等水文情势变化特征可为水域安全管理和生态系统功能恢复提供一定科学依据.利用城陵矶等代表性站点水文数据以及Landsat5、8卫星遥感数据,综合分析了 2000-2020年洞庭湖水文情势变化特征,并从流域层面分析了来水对洞庭湖水文情势变化的驱动影响.结果表明:(1)洞庭湖整体平均水位年际波动较大,同时年内水位变化趋势较为明显,具有明显的丰枯水期;(2)洞庭湖最大水域面积减少,但最小水域面积增加;(3)洞庭湖水体有效连通性大幅度下降,W-E方向的连通性提高,而N-S方向的连通性下降;(4)三口(藕池口、松滋口、太平口)水位和流量变化与湖区整体水文情势关系更加密切,其中藕池口对湖区水文情势影响最大.
Abstract
The hydrological regime plays an important role in determining the quality of aquatic ecosys-tems.Studying the hydrological changes in lakes,rivers and other water bodies provides a scientific basis for water safety management and ecological restoration.In this study,we analyzed change in the hydro-logical regime of Dongting Lake from 2000 to 2020 and explored the effect of inflowing water on chang-es in hydrology using random forest regression.The study was based on hydrological data from 8 repre-sentative stations(Chenglingji,Yingtian,Nanzui,Yangliutan,Taoyuan,Mituosi,Shadaoguan,Kangjia-gang)and Landsat 5 and 8 satellite remote sensing data.Results show:(1)In the past 20 years,the annual average water level of Dongting Lake fluctuated widely,with water levels in 2002,2005,2012 and 2016 significantly higher than the average,and levels in 2006 and 2011 significantly lower than the average.The changes in water level within a year were more regular,displaying a single peak and distinct levels in the wet and dry periods.(2)The maximum annual water area of Dongting Lake decreased by 99.70 km2 from 2000 to 2020,but the minimum water area increased by 188.85 km2.(3)The effective connectivity of the water surface of Dongting Lake decreased significantly over the past 20 years.In general,connec-tivity increased along the west-east axis and decreased along the north-south axis.(4)Changes in water level were closely related with flow rates of the three major inlets(Ouchikou,Songzikou,and Taipingkou)and closely related to the overall hydrological regime of Dongting Lake,with Ouchikou having the largest impact.
维普
万方数据