Abstract
Surface suspended sediment concentration (SSSC) in the global ocean varies across multiple spatial and temporal scales, driven by complex mechanisms. Focusing on the highly turbid Bohai Sea off northern China, this study derived SSSC during 1984–2021 using high‐resolution Landsat remote sensing data. Results revealed a significant declining trend, showing a basin‐averaged decrease of 8.8 mg/L (24.0%) over 38 years, with seasonal reductions of 23.7%–30.5% in spring, autumn, and winter, while a slight increase occurred in summer. Spatially, SSSC decreased by up to 32.9% in coastal waters and by 8.5% in the central Bohai Sea. The average wind speed observed at 24 meteorological stations along the coast decreased by 0.84 m/s (23.3%). During 2004–2021, SSSC derived from individual satellite images was correlated with hourly wind speeds, with wind leading SSSC by approximately 2 hr in shallow areas and by 4–10 hr in deep waters. On average, 1 m/s decrease in wind speed corresponds to 6.8 mg/L decrease in SSSC for the entire Bohai Sea, by more than 15 mg/L in the shallow waters of Laizhou Bay and Bohai Bay, and by 0.5–2.5 mg/L in the central basin. The weakening wind field accounts for approximately 65% of the total SSSC decline over the whole Bohai Sea. Following the Yellow River's 1996 northward diversion, SSSC slightly increased near the new mouth and decreased near the old one. The SSSC‐wind speed correlation is lower near the new mouth due to greater direct influence of river sediment discharge.