论文利用2005年Terra/MODIS卫星8天合成的250m地表反射率数据(MODIS Terra Sur-face Reflectance 8-Day L3 Global 250 m:MOD09Q1)构建的时间序列数据集,通过计算NDVI指数,结合典型地物的谱间特征,并借助SRTM数字高程数据,采用多源信息提取的方法对洞庭湖地区2005年水域面积变化进行了动态监测。结合Terra/MODIS数据特点,提出了全年最大淹没时间指数的概念,并通过对该指数的构建,完成了对洞庭湖地区重点水域的淹没风险评价。结果表明:①文中提出的基于Terra/MODIS MOD09Q1数据的多源信息水体提取方法,通过更高空间分辨率ENVISAT/ASAR数据以及水文测站水位数据的检验表明,是切实可行的;②2005年洞庭湖地区水域面积变化特征总体表现为,在11~4月份期间水域面积较小,而在5~10月份期间较大。其中,4月份最小,9月份最大,两者相差了几乎1.5倍,受地区季节性降雨的年内分布规律及长江主汛期的影响显著;③通过全年最大淹没时间指数的计算发现,占研究区总面积84.13%的年内持久陆地和持久水域区域,基本上没有防洪压力,而剩余的15.87%的年内变化水域,由于潜在淹没风险的存在,则需要抗洪防险部门进行重点防控;④文中多源信息水面提取方法的实现以及全年最大淹没时间指数概念的提出,为今后更加深入地探讨三峡工程建成运营对洞庭湖地区水域变化以及江湖关系的影响奠定了基础。 In this paper, the time series data set of 250m surface reflectance data (MODIS Terra Sur-face Reflectance 8-Day L3 Global 250 m: MOD09Q1) synthesized in 2005 by Terra / MODIS satellite was used to calculate the NDVI index, Based on the SRTM digital elevation data, the multi-source information extraction method was used to monitor the change of water area in Dongting Lake in 2005. Combined with the characteristics of Terra / MODIS data, this paper proposes the concept of maximum flooding time index in the whole year, and through the construction of this index, has completed the evaluation of inundation risk of key waters in Dongting Lake. The results show that: (1) The multi-source information water extraction method based on Terra / MODIS MOD09Q1 data presented in this article is feasible through the higher spatial resolution ENVISAT / ASAR data and the hydrological station water level data; (2) The overall change of the area of ​​water area shows that the area of ​​water area is small during the period of November to April, and it is larger in the period of May to October. Among them, the minimum was in April and the maximum in September, with a difference of almost 1.5 times, which was significantly affected by the distribution pattern of regional seasonal rainfall and the main flood season in the Yangtze River. (3) According to the calculation of annual maximum submergence time index, In the area with long-term land and long-lasting water throughout the year with a total area of ​​84.13%, there is basically no flood control pressure. However, the remaining 15.87% of the year-changing waters need to be prevented and controlled by the flood control and risk prevention department due to the potential submergence risk. The realization of water source extraction method and the concept of maximum flooding time index in the year provide a basis for further discussion on the impact of the completion and operation of the Three Gorges Project on the change of waters in the Dongting Lake area and the relationship between rivers and lakes.