Grain size of sediments in five rivers on the Eurasian continent

All five sampling sites exhibit river erosion. Sampling site 1 is located upstream of the Vylyui River, an important tributary of the Lena River, and is situated in the Siberian permafrost zone. The terrain is predominantly flat plains and lowlands, surrounded by coniferous forests and marshes. The annual temperature difference can exceed 80°C, making it one of the regions with the largest annual temperature differences globally. Sampling site 2 is located near the Lena River basin, which has numerous tributaries. The surface is covered by permafrost, with terrain primarily consisting of plains and lowlands, and局部 areas featuring hills and coniferous forests. This region experiences extremely cold and prolonged winters, short and warm summers, and a significant annual temperature difference. Sampling site 3 is the largest tributary of the Songhua River, with diverse terrain within the basin and a typical temperate monsoon climate, characterized by cold, dry winters and warm, humid summers. The basin contains numerous wetlands and lakes, which play an important role in regulating the climate and maintaining ecological balance. Sampling site 4 is located in a basin with a warm temperate monsoon climate, with an annual average temperature of approximately 14.9°C, dominated by southwest winds, featuring a mild climate and humid air. The Kangwang River basin has a relatively flat terrain and is part of the Huanghuai Plain. Sampling site 5 is located near the Yellow River estuary, which is the core area of the Yellow River Delta. The elevation is mostly below 10 meters, with the surface dominated by wetlands, tidal flats, and saline-alkali land. The region has a warm temperate semi-humid continental monsoon climate, with strong winds in spring, high humidity in summer, and dry air in winter.