Study on the seasonal variation of the suspended sediment distribution and transportation in the East China Seas based on SeaWiFS data

Abstract

The monthly mean suspended sediment concentration in the upper layer of the East China Seas was derived from the retrieval of the monthly binned SeaWiFS Level 3 data during 1998 to 2006. The seasonal variation and spatial distribution of the suspended sediment concentration in the study area were investigated. It was found that the suspended sediment distribution presents apparent spatial characteristics and seasonal variations, which are mainly affected by the resuspension and transportation of the suspended sediment in the study area. The concentration of suspended sediment is high inshore and low offshore, and river mouths are generally high concentration areas. The suspended sediment covers a much wider area in winter than in summer, and for the same site the concentration is generally higher in winter. In the Yellow and East China Seas the suspended sediment spreads farther to the open sea in winter than in summer, and May and October are the transitional periods of the extension. Winds, waves, currents, thermocline, halocline, pycnocline as well as bottom sediment feature and distribution in the study area are important influencing factors for the distribution pattern. If the 10 mg L-1 contour line is taken as an indicator, it appears that the transportation of suspended sediment can hardly reach 124°00′E in summer or 126°00′E in winter, which is due to the obstruction of the Taiwan Warm Current and the Kuroshio Current in the southern Yellow Sea and the East China Sea.