Reconstructing the suspended sediment load of the Yellow River since 1470 CE using the Drought and Flood Index

Abstract

The Yellow River of China is well known around the world for its large sediment yield and suspended sediment load (SSL). To better understand the cause of SSL variability, we need long-term perspectives that go back 100–1000yr. However, few long-term reconstructions have been published, especially with high temporal resolution. In this study, we show that the Drought and Flood Index (IDF) based on historical document analysis can be used as a proxy to reconstruct the SSL, the high-flow season (June–October) stream flow, and the annual precipitation of the middle Yellow River from 1470–1919. The calibration equation explains 57.6% of the variance in the SSL produced from the drainage area between the Hekouzhen and Longmen stations on the Yellow River. Variation in the IDF reflects the variation in the summer monsoon in China that causes the variation in water vapor transport, precipitation, and soil erosion. These links explain the mechanism of reconstructing the SSL based on the IDF. The reconstructed 450yr series shows that the SSL responds sensitively to El Niño events. The reconstructed SSL may be used as a baseline to assess the effects of human activity on the SSL for the period after 1970, and the reduction in SSL for the period 1971–2013 was estimated as 4.09×108t/yr, accounting for 48.9% of the annual SSL induced by only climate.