Numerical simulation-aided MODIS capture of sediment transport for the Bohai Sea in China

Traditionally, the establishment of a remote-sensing retrieval model depends on in situ data acquired by expensive and considerably labour-intensive field surveys, but now we can benefit from numerical simulation. In this study, after considering the advantages of numerical simulation in extending the spatial and temporal suspended sediment concentration (SSC), we propose an approach to establish an SSC retrieval model from remotely sensed images with the aid of a numerical model for the Bohai Sea in China. First, significant correlation, between simulated SSC and atmosphere-corrected water-leaving reflectance derived from Moderate Resolution Imaging Spectroradiometer (MODIS) band-1 images, was investigated to demonstrate a novel SSC retrieval model. The synchronous data from remote sensing and numerical simulations enabled the removal of spatial and temporal differences between satellite and in situ measurements. Based on this retrieval model, the SSC distribution pattern was simulated in two scenarios to separate river sediment discharge from the overall process of resuspension. The results indicate that the distribution pattern of the simulated surface SSC without sediment discharge from the Yellow River in most study areas generally matched that derived from MODIS images, except for the estuarine area. The surface SSC 30-40 km away from the estuaries are dominated by sediment discharge from rivers. The proposed method, the numerical simulation-aided SSC retrieval MODIS model, can efficiently capture the sediment transport in the Bohai Sea, which is helpful for operational monitoring of the water environment in estuary and coastal waters.