RIVER PLUME MIXING PROCESSES INDUCED BY BREAKING OF REMOTELY GENERATED INTERNAL TIDES

Abstract

 This study presents river plume mixing induced by internal tide breaking over a shallow slope using a nonhydrostatic model SUNTANS. When a low salinity layer exists in the surface rive plume layer, internal tide disturb the surface layer resulting in internal soliton wave packets propagating toward the coast. Two types of internal soliton wave packets are generated in the surface laeyr during run-up and receding phases of internal tides. The internal soliton wave packets enhance the surface kinetic energy in shallow coastal area. In addition, the internal soliton wave packets increase the onshore ward internal wave energy flux, possibly causing energy dissipation in shallow coastal areas. The surface kinetic energy and internal wave energy flux are intensified as the surface low salinity layer decreases, which implies that the rate of river discahrges modulated by precipipations would influence internal tide energy toward the coast.