Cyanobacteria bloom water has obvious plant characteristics "steep slope effect" in the near infrared wavebands and is the main basis for satellite monitoring of cyanobacteria blooms. The aquatic macrophytes have similar spectra characteristics with cyanobacteria blooms. On the optical remote sensing image, the remote sensing monitoring method based on the near infrared steep slope effect cannot realize synchronous monitoring of cyanobacteria blooms and aquatic macrophytes. Normally, the aquatic macrophytes in Taihu Lake are mainly located in Zhenhu Bay, Guangfu Bay, Xukou Bay, East Taihu Lake and other regions and differ from the bloom prone areas (west and north areas of Taihu Lake). Normally, masking treatment is made for East Taihu Lake aquatic macrophytes area in the remote sensing monitoring of cyanobacteria blooms in Taihu Lake and the occurrence of bloom will no longer be considered in the mask areas. Since 2012, with the in-depth implementation of Taihu Lake pollution remediation and ecological restoration measures, a large number of aquatic macrophytes (mainly including potamogeton crispus, potamogeton malaianus and nymphoides peltatum) appear in Taihu Lake Meiliang Lake, Gonghu Lake and the South Taihu Lake and other algae-prone areas with their area of up to dozens of square kilometers. The traditional monitoring method will wrongly determine the aquatic macrophytes as cyanobacteria bloom, which may seriously affect the monitoring accuracy. In addition, in order to reduce the adverse effects of a large number of aquatic macrophytes on shipping, the local authorities will regularly have a harvest, resulting in man-made changes in the aquatic macrophytes areas. Furthermore, the dominant aquatic macrophytes in Taihu Lake have different life histories, significant differences in the growth periods and significant change in the temporal and spatial distribution of aquatic macrophytes. According to the above factors, the way of fixing the aquatic macrophytes areas cannot be able to adapt to the temporal and spatial changes of aquatic macrophytes and cannot meet the requirements for remote sensing high-precision monitoring of cyanobacteria bloom.

Academy of Sciences innovatively proposes cyanobacteria and macrophytes index (CMI) based on the spectra difference of cyanobacteria blooms and aquatic macrophytes in blue, green and near infrared wavebands and successfully realizes MODIS satellite synchronous monitoring of cyanobacteria bloom, floating algae and emergent/floating macrophytes with its accuracy of 86%. This method can effectively realize separation and extraction of cyanobacteria blooms and aquatic macrophytes by remote sensing technology and provide important technical support for further promoting prediction and pre-warning accuracy of cyanobacteria bloom in Taihu Lake.

Recently, the research achievements were publicly published in the Remote Sensing, a mainstream publication in the field of remote sensing science (http://www.mdpi.com/2072-4292/9/2/133/htm).