东洞庭湖水面面积变化监测及其与水位的关系

开展东洞庭湖水面面积长时间变化监测研究对于湖区洪涝旱灾监测、灾害评估等具有重要意义。采用2000~2017年的经过辐射一致性校正的Landsat Collection 1遥感数据集，在ENVI遥感数据处理平台下采用4种常见的水体提取方法（单波段阈值、多波段谱间关系、水体指数、支持向量机）开展了水面面积遥感提取方法比较及东洞庭湖区长时间序列水面面积提取，以此数据为基础开展了东洞庭湖区近18年来湖区水面面积年内和年际变化研究，并探讨了水面面积与城陵矶水文站水位之间的相关关系。结果显示：Landsat Collection 1遥感数据集具有较高的空间和时间分辨率，可以满足东洞庭区长时间序列水面面积提取，且水面面积提取精度较好；采用支持向量机方法提取的湖区多年水面面积平均值为569.9 km2，丰水期水面范围波动较大，而枯水期变化较小；湖区水面面积变化与城陵矶水位变化存在紧密相关关系，不管线性模型还是多项式模型均能准确地描述两者变化关系，受湖区地形分布特征影响，水面面积与水位之间的关系在丰水期较紧密，而枯水期两者之间的相关关系明显降低。

Monitoring the Changes of Water Area and Its Relation with Water Levels of Hydrological Station in East Dongting Lake

Monitoring the long-term changes of water area is of great significance for the flood and drought monitoring in the East Dongting Lake. In this paper, the remote sensing data set of Landsat series Collection 1, which has been corrected by radiation consistency from 2000 to 2017, is used to extract the long-term sequence water surface area data of the East Dongting Lake area. Four common water extraction methods (single band threshold, multi band spectral relationship, water index, support vector machine) are used under ENVI software to carry out the comparison of the best or most suitable water surface area extraction method in study area. And then, the annual and inter-annual changes of the water surface area of the East Dongting Lake in the past 18 years are studied, also the correlation between the water surface area and the water level of Chenglingji hydrological station is discussed.Our results show that: (1) The remote sensing data set of Landsat collection 1 has a high spatial and temporal resolution, which can meet the requirements of long-time series water surface area extraction in our study area, also the accuracy of water surface area extraction is high regardless of the flood period or water lowering period; (2) During our study period, the average value of multi-year water surface area extracted by support vector machine of the East Dongting Lake is 569.9 km2 , which fluctuates greatly in wet season, but changes little in dry season; (3)There is a close relationship between the accumulation water area change and the water level change in Chenglingji hydrological station. Both linear model and polynomial model can accurately describe the relationship between them; (3) Influenced by the topographical distribution characteristics of the East Dongting Lake, the relationship between the water area and water level is relatively close in the wet season, while the relationship between the two is significantly reduced in the dry season.