Suspended Particle Size Retrieval Based on Geostationary Ocean Color Imager (GOCI) in the Bohai Sea

The suspended particle size has an important effect on the settling velocity of particles, the penetration of sunlight into the sea and the transmission of sound. It is of importance to investigate the spatio-temporal distribution of suspended particle size. In this paper, a new empirical model was developed based on Geostationary Ocean Color Imager (GOCI) data for retrieving the median suspended particle size (d50), and then, the spatio-temporal variation in GOCI-retrieved d50 was analyzed over the Bohai Sea. The results showed that the new model gained the satisfactory retrieval results in the Bohai Sea. Spatially, median particle size in the Bohai Sea showed an obvious onshore-offshore gradient, which was smaller in the coastal waters, especially in the Laizhou Bay, the Bohai Bay, and the Liaodong Bay while larger at the Bohai strait and the northwest part of central Bohai Sea. Hourly variations of d50 data depicted the short-term dynamics of suspended sediments. The daily-averaged d50 had a similar pattern of spatial distribution and numerical values to the hourly data but with a distinct temporal variation. In addition, the findings of this study suggested the possible effects of tide, wind, turbulence and riverine input on the median particle size distribution.