Spatiotemporal variations in suspended sediments over the inner shelf of the East China Sea with the effect of oceanic fronts

Suspended sediments are important contributors to the material exchanges between the sea surface and bottom and between the coastal waters and shelf seas. The East China Sea (ECS), connecting the Chinese continent and the western Pacific, receives a large amount of Yangtze River-delivered sediments. However, due to the climate change and intense human activities in recent years, the amount of Yangtze River-delivered sediment decreased by two thirds. Fewer work has been conducted on the accompanying changes of suspended sediment concentration (SSC) over the inner shelf of the ECS. Thus, in this study, based on the long-term water temperature, salinity, and SSC data derived from MODIS during 2003-2018, the spatiotemporal variations of SSC and the effects from oceanic fronts were studied. The results indicated a typical seasonal change of the SSC with the effect of a thermocline in summer and thermal-saline front in winter, respectively. Regarding the long-term variation of the SSC from 2003 to 2018, it displayed significant differences in spatial distribution. The SSC anomaly exhibited the opposite phases between the north and south parts of 28-29 degrees N and between the landside and seaside of the front at the isobaths of 20 m-40 m along the Zhe-Min Coast. In general, wind is the controlling factor that affects the SSC in most area of the Zhe-Min coast, especially in spring and winter seasons.