Contrasting Response of Circulation to Tidal/Non-Tidal Forcing in the China Sea Multi-scale Ocean Modeling System (CMOMS)

Abstract:

Tidal forcing not only enhances the internal energy of the oceanic circulation through the amplified mixing processes, but also strengthens the sub-tidal circulation through the flow-topography interaction over constricted bathymetry. China Sea (CS) is formed by semi-enclosed marginal South China Sea (SCS) and shallow shelf seas of Bohai, Yellow and East China Sea (ECS) through the link of Taiwan Strait. The circulation of CS connects with western Pacific Ocean by shelf break in ECS and through Luzon Strait in SCS, with Sulu Sea through Mindoro Strait and with Java Sea through Karimata Strait. This study examines the tidal forcing effect on the China Sea circulation by contrasting the circulation with and without tidal forcing obtained from the China Sea Multi-scale Ocean Modeling System (CMOMS). We adopt a newly developed open boundary condition for the limited regional model that is physically comparable between the tidal and non-tidal simulations, and investigate the circulation responses to the tidal forcing in the western Pacific current system of the deep basin, the flow exchanges through the straits around the CS, the circulation in broad shallow continental shelves as well as in the holistic CS circulation itself.