Pre-operational monitor system of large inland lake water quality with MODIS imagery

Abstract

EOS\MODIS data have been proved a suitable and relative low-cost complementary tool to monitor large inland lake water quality for its re-visit frequency, moderate spatial and spectral resolution and appropriate channels designed for inversing water quality parameters. In this study, by the support of hi-tech research and development program of China, Lake water quality remote monitoring pre-operational system (LWQRMPS) was constructed aimed for practical monitoring of Taihu Lake water quality. The main water quality parameters including Chl-a and SPM, TN and TP inversion algorithm were developed. These parameters were obtained every month from time series fusion satellite data. With the routine trophic state evaluation system, the water quality was assessed every month based on the above retrieved MODIS water quality parameters, varied level of eutrophic area was computed. The obvious high reflectance in near-infrared spectrum caused by blue-green algal bloom support the application of 250m MODIS data in the algal bloom emergency monitor. Therefore, MODIS data were utilized successfully for inversing water quality parameters, evaluating eutrophication status, and detecting algal bloom in near real time. Standard thematic maps were produced and distributed to corresponding management departments. The accuracy of products and retrieve algorithm for operational use were tested with separate data sets. The result suggested that system is good enough for practical monitoring water quality of large size lakes and acquired identification.