Modeling the Effects of Extreme Drought on Pollutant Transport Processes in the Yangtze River Estuary

摘要: Water resources in the Yangtze River Estuary (YRE), which is vital water supply for Shanghai, decreased by approximately 2.45 Gm3 2006, second-worst recorded drought year. A numerical model was developed to investigate effects of this extreme on pollutant transport processes YRE. The calibrated against observations and displayed good agreement. Residence time, a critical hydrodynamic indicator, implemented indicate processes. Numerical experiments were conducted examine possibly drought-induced influences. results demonstrated that influences varied spatially temporally, these could partly explain observed temporal spatial variations total nitrate 2006. area most susceptible north branch with 2-11 days' extension residence time. As occurred both high normal periods, its more significant during period saltwater intrusion into branch. also introduced lag timescale five days diminishing seaward advection flux freshwater discharge. In magnified tidal influence contributed than usual structuring transport, as intensely associated flow cycle.