Impacts of tidal currents and Kuroshio intrusion on the generation of nonlinear internal waves in Luzon Strait

The analysis of remotely sensed images shows that two kinds of nonlinear internal solitary waves (ISWs) in the forms of single ISW and groups of ISWs are commonly seen in Luzon Strait (LS), with larger occurrence during spring tides. A 2-D numerical model with idealized topography is then used to investigate the generation processes of ISWs in LS. The model results confirm that the ISWs are likely generated during spring tides with strong tidal currents. The results further suggest that the ISWs can be generated by two mechanisms: the evolution of depression and the internal mixing disturbance. Our simulations also show that the Kuroshio intrusion to LS or South China Sea through LS increases the occurrence of generating internal mixing and groups of ISWs. Both remotely sensed images and numerical simulations suggest the existence of a distance between the actual locations where ISWs are generated and where the strongest flow occurs.