Simulation of temperature, salinity and suspended matter distributions induced by the discharge into the East China Sea during the 1998 flood of the Yangtze River

A three-dimensional model simulated the distributions of current, water temperature, salinity and suspended matter in the Yangtze estuary area and the East China Sea caused by the discharge of freshwater from the Yangtze (Changjiang) River for 3 years from May 1996 to April 1999. The calculation was conducted using a longitude–latitude mesh of 5 min × 5 min, in assimilating the daily average discharge from the Yangtze with the meteorological conditions on the sea surface obtained from the atmospheric global circulation model (European Centre for Medium-range Weather Forecasts, ECMWF) and the daily average precipitation over the sea surface obtained from the TRMM (Tropical Rainfall Measuring Mission) satellite data. The calculated water temperatures were in excellent agreement with the measurement data observed by the marine meteorological buoy robot (ST22001). For the surface salinity distribution on the east–west transection line across the East China Sea and the cross-sectional distribution of salinity in the Tsushima Strait, the calculated values were in excellent agreement with the observed data. During the Yangtze flood in 1998, turbid water was discharged in repeated pulses from the Yangtze and penetrated the East China Sea. This behavior of suspended matter discharged from the Yangtze was clearly identified by the 3D model results in salinity, suspended matter and current distributions. The model results revealed the fact that the freshwater and suspended matter originating from the Yangtze crossed the East China Sea and reached as far as the coasts of Kyushu, the Japan Sea and the Pacific coast of mainland Japan.