Long-term Trend and Change Point Analysis on Runoff and Sediment Flux into the Sea from the Yellow River during the Period of 1950-2018

Sui, Y.; Shi, H.; You, Z.; Qiao, S., and Sun, J., 2020. Long-term trend and change point analysis on runoff and sediment flux into the sea from the Yellow River during the period of 1950-2018. In: Zheng, C.W.; Wang, Q.; Zhan, C., and Yang, S.B. (eds.), Air-Sea Interaction and Coastal Environments of the Maritime and Polar Silk Roads. Journal of Coastal Research, Special Issue No. 99, pp. 203–207. Coconut Creek (Florida), ISSN 0749-0208.Based on the observed runoff and sediment data from Lijin hydrological station during the period of 1950–2018, this paper addressed the long-term change characteristics of runoff and sediment fluxes into the sea from the Yellow River. The Mann-Kendall test was adopt to estimate the long-term trends in the runoff and sediment time series. The Mann-Whitney-Pettitt (MWP) test were used to determine the change points of runoff and sediment time series. It could be concluded that the annual runoff and the sediment fluxes decreased significantly at the rates of –6.17×109 m3/a and –0.213×109 t/a, respectively. The changes during the flood season were more dramatic than in the dry season, especially for the sediment flux. Different significant change points are detected in the runoff and sediment time series. The changing point for the runoff occurred in 1968, 1985, and 2002 and those of sediment flux in 1968, 1985, and 1996, respectively. The negative long-term change trend and the occurrence of change points are highly associated to natural variation and human activities in the Yellow River basin. The occurrence time of some change points accords even with man-made events.