Abstract: Due to eutrophication,E. prolifera disasters have frequently occurred in China’s Yellow Sea since 2007, which have become the most serious ecological disaster in the Yellow Sea. Satellite remote sensing has the advantages of largescale monitoring and instantaneous monitoring, and is one of the most important monitoring means of E. prolifera disaster. Moderateresolution imaging spectroradiometer (MODIS) image is the main data source of E. prolifera operational monitoring because of its large size, high temporal resolution and free distribution. There are many errors in E. prolifera area derived from NDVI threshold, because of mixed pixels in the coarse resolution (250 m) MODIS images. In order to solve this problem, we extracted the E. prolifera area from the MODIS image with the spatial resolution of 250 m by combining the linear spectral mixture decomposition method and NDVI threshold method. A large area and its threeinner subareas were selected for the accuracy evaluation based on the data of E. prolifera extracted from quasisynchronous ZY-3 satellite with 5.8 m spatial resolution. We found that the error of E. prolifera area, extracted from the linear mixed model with a NDVI threshold of 0.04, was the smallest, and the errors of the large area and its three subareas were 7.86%, 14.59%, -7.65% and -0.15% respectively. Hence, we provide a method that can effectively eliminate interference from the E. prolifera mixed pixel and non E. prolifera pixel, and greatly improve the inversion precision which is stable in different regions. This method can provide support for the management decision and evaluation of E. prolifera ecological disaster.

Key words: inorganic sulfur form, bare flat, seaward invasion, Spartina alterniflora marsh, Minjiang River estuary