Poyang Lake is the largest freshwater lake in China, and it plays an important role in flood control regulation and storage and biodiversity protection. Water eutrophication in Poyang Lake has been considered to be an obstacle to aquatic environment protection and regional sustainable development. Chlorophyll-a concentration is one of the most important indices of water eutrophication. This application builds seasonal chlorophyll-a concentration retrieval models using a semi-analytical model. Quarterly distributions of chlorophyll-a concentration from 2009 to 2012 are explored using multi-spectra data from a moderate-resolution imaging spectroradiometer (MODIS).
With the WebGIS technology, the application of spatial distribution of the seasonal chlorophyll-a concentration in Poyang Lake, China (2009-2012) has been released. This application shows the measured chlorophyll-a concentration data in January, April, July, and October from 2009 to 2012. MapServer is used to release Web Map Service (WMS) referring the international specification. The Combination of data and MapBox tiles has been used by OpenLayers to generate the map view. When the app page opened, the satellite image could be visualized as the map service. In the map operation on the right side of the app page, users can select different years and months to view the corresponding data map.
Selecting GIS data operation in the sidebar navigation, users can see the corresponding options (year and month) and click the drop-down arrow to display the year and month lists, including the years from 2009 to 2012, and the months include January, April, July,and October. In the bottom right corner of the app page, users can see application-related documents and information which are classified by label control. The user can choose more to get more readings.