Multiple Timescale Suspended Sediment Concentration Variations in the East China Seas Indicated by Satellite Observations

Suspended sediment concentration (SSC) in the East China Seas (ECSs) is modulated by a host of physical processes such as wind waves, tides and circulations on different timescales, which in turn leads to SSC variations on corresponding timescales. SSC variations have attracted enormous interest in the ECSs community owing to its profound impact on biogeochemical processes. However, the SSC variations and its modulation mechanisms remains limited understood. The aim of present study is to quantify the SSC variations on multiple timescales (intra-tidal, spring-neap, seasonal and long-term timescales) and their modulation mechanisms using high spatial-temporal resolution satellite remote sensing data from MODIS and GOCI. The results indicate that in the ECSs (area of 13.01×10⁵ Km²), the monsoon winds play the most important role in modulating SSC, causing strong SSC variation (> 30 mg/L) in 8.1% area (1.07×10⁵ Km²), and medium SSC variation (5-30 mg/L) in 29.5% area (3.89×10⁵ Km²). The tidal current variations on intra-tidal timescale play the second important role in modulating SSC, causing strong SSC variation in 0.7% area (0.10×10⁵ Km²), and medium SSC variation in 26.2% area (3.41×10⁵ Km²). The spring-neap tidal current variations also have significant influence on modulating SSC, causing strong SSC variation in 0.15% area (0.02×10⁵ Km²), and medium SSC variation in 14.1% area (1.83×10⁵ Km²). The SSC variations on the long-term timescale (10 years) are not significant, as strong SSC variations are only observed in the Bohai Sea with an area of 0.008×10⁵ Km². The SSC datasets of this study provide the research community of the ECSs an important data source for a better understanding of SSC spatial-temporal variability and its modulation mechanisms in the ECSs.