HYDRODYNAMIC SIMULATIONS OF THE YATSUSHIRO SEA, JAPAN

摘要

The Yatsushiro Sea, Kyushu, Japan, includes the Minamata Bay, known by the contamination with toxic mercury in 1958. Measurements have shown that some mercury has been transported from the Minamata Bay out to Yatsushiro Sea. A study of hydrodynamic circulation of the Yatsushiro Sea has been carried out to be used further on for the simulations of pollutant transport. A 3D numerical model PCFLOW3D has been validated by measurements of tidal circulation. Further numerical simulations have shown: (a) tidal forcing is the most important forcing factor, causing velocities over 6 knots in some of the straits; (b) the second important forcing factor is wind; typhoon winds can generate velocities, which are of the same or even greater magnitude as tidal velocities everywhere, except near the straits; (c) the resulting hydrodynamic velocity fields are reliable basis for further simulations of mercury transport and fate.