Changes in suspended sediment concentration in the coastal waters of the Western Pacific from 1984 to 2022

Abstract

Asian rivers are significant contributors to the world’s coastal sediment flux and the Western Pacific Coast (WPC) receives most of them. In recent years, Natural changes and human activities constantly change the suspended sediment concentration (SSC) in waters of the WPC; resulting in significant changes in coastal and marine systems, consequently altering the global biogeochemical cycle. However, monitoring these changes is difficult, confounded by the lack of observational data and unavailability of globally SSC algorithms. Here, based on the platform of Google Earth Engine, we retrieved the SSC in the waters where stretching 10 nautical miles from the WPC using multi-source imagery from Landsat-TM/ETM+/OLI sensors (from 1984-2022) to obtain its long-term dynamics using 3 different SSC algorithms. The results indicate that the 3 retrieve algorithms obtained satisfactory results in temporal-spatial variation trend of SSC. We discovered that some estuaries in the WPC show significant decreasing changes. For example, the spatial distribution of SSC in the Pearl River Estuary (PRE) represented a trend of high along the west coast and low along the east coast. Over the past 39 years, the SSC showed a relatively evident decreasing trend in most PRE regions; In the Yangtze Estuary (YRE), the SSC in the outer estuaries was generally significantly higher than that in the inner and SSC demonstrated an overall declining pattern in time; For the Yellow River Estuary, the highest of SSC is located a peripheral zone in front of the estuary, and also showed an overall decreasing trend in time.