Remote sensing inversion of particle size characteristics of surface sediments on tidal flats in the Yellow River Delta

Grain size distribution is a fundamental characteristic of sediments, serving as a crucial means to comprehend the water-sand process, the evolution of siltation, and the geomorphic evolution of tidal flats. Studying the grain size of surface sediments on tidal flats is essential for understanding the hydrodynamic processes and depositional characteristics of these environments. This study focuses on the Yellow River Delta, using Landsat data to establish a regression model that estimates the spatial distribution of surface sediment grain size over the past 40 years. The results indicate that from 1986 to 2024, changes in hydrodynamic conditions resulting from the diversion of the Yellow River led to an decreasing grain size trend from sea to land in the tidal flats of the Diaokou River. Conversely, the new estuary shows a decreasing grain size trend from the land to the sea, providing a basis for the protection and restoration of the tidal flats in the Yellow River Delta.