Recent Changes of Riverine Sediment Fluxes from the Third Pole

 The Third Pole is the headwater of major rivers in Asia, which provide water resources for more than 2 billion people downstream. Compared with discharge, riverine sediment flux is a more sensitive variable in response to climate and land surface process changes, and also as an important index to quantify regional land degradation and soil resource changes. In this study, eight rivers originated in the Third Pole, including YerKang River, Shule River, Heihe River, Yarlung Tsangpo River, Nujiang River, Yellow River, YangTze River and Lancang River, were selected to study the variation of sediment flux in the source zone or upper reaches. Firstly, the amount and spatial variation of runoff depth and sediment yield of these rivers were explored. Secondly, the changes of riverine sediment fluxes in recent decades (1960-2017) were analyzed, with the spatial and temporal variations of sediment flux compared to climate (temperature, precipitation) and land surface process (glacier, frozen soil, vegetation cover) factors. Thirdly, the uncertainty of sediment flux variation associated with interaction of multi-factors were discussed. Finally, the significant impacts of sediment flux variation on the Third Pole environment and the safety of hydropower projects was pointed out with typical cases.