Coupling remote sensing retrieval with numerical simulation for SPM study—Taking Bohai Sea in China as a case

Study of suspended particulate matter (SPM) transport in a coastal area, traditionally supported by field observation and numerical simulation, benefits now from numerous available remotely sensed ocean color images. Numerical simulation of SPM dynamics can be the supplement to remote sensing data which response the discrete states for different point-in-times. It would be helpful for monitoring coastal water environment in a real sense if remote sensing can be coupled with numerical simulation to get a promising water environmental dynamics in time and space domain. In this study, an approach coupling ocean color image retrieval with numerical simulation of SPM transport is proposed. Instead of traditionally specifying the spatial-constant SPM concentration as an initial condition of sediment transport models, the spatial-variant SPM concentration retrieved from MERIS image initializes the models. And the SPM resuspension and deposition can be interactively inspected and verified. Combining the simulated results with the remote sensing retrieved results, the parameters of hydrodynamic model and sediment transport model can be calibrated. The Bohai Sea in China is selected to test the approach. An optimized group of parameters are calibrated by using the SPM concentration retrieved from MERIS image in the Bohai Sea. Compared with the SPM initialization of spatial-constant, the spatial-variant SPM input retrieved results can quickly response to the changes of sediment concentration in real sense. The results show a well agreement with the in situ measurements. The results show that the approach is good at simulating SPM dynamics in clear waters with a SPM concentration lower than 20 mg/l and more effective in the area with less land source affected. The study suggests that the proposed approach is effective for monitoring coastal water environment roundly and three-dimensionally.