Monitoring For Eutrophication Of Dongting Lake Based On ETM+Image

With the development of society and the improvement of economy, problems such as the environmental pollution and ecological deterioration are more and more serious, and water pollution is more and more prominent as well. Therefore, it is very important to enhance water quality monitoring. Water quality monitoring is the base of water quality evaluation, and is also the basis so that related departments can take measures to prevent and control water pollution. Traditional monitoring method is time-consuming and strenuous, and is hard for us to obtain the information of overall water quality of lake. Whereas the new method has advantage in wide extent monitoring, such as high-speed, low cost, and long-term dynamic monitoring conveniently, and so on. It also has much potential in lake quality monitoring.According to studying the methods and techniques of monitoring water quality of inland through Remote Sensing, the author presented a method, which is used to quick monitor water quality after making use of low-middle resolution ETM+data. The author used this method to monitoring water quality of Dongting Lake. First, after comparison and analysis of single waveband threshold technique, method based on the relevance of spectrums and index model, MNDWI, one of index models was used to monitor quality of the Dongting Lake. Then, Spectral Unmixing Model, vegetation index model and abnormality temperature of lakd surface model were established to evaluate water quality of the Dongting Lake, water quality distribution figure could be got. At last, accuracy analysis of result was implemented.In the research of monitoring Dongting Lake water eutrophication through ETM+data, the author used three models of decomposition of linear mixed pixel,difference vegetation index and water surface temperature retrieval. These models do not require a large amount of field observation data, and can get the eutrophication figures quickly and easily with certain accuracy. Consequently this method is of a highly practical value for rapid monitoring eutrophication, and it can also provide certain theory evidence for the decision-making of water environment management.