Tide is a primary driver for ocean mixing and thereby influences the internal stratification, water mass distribution, and upper ocean heat content. The marginal seas of the North Pacific, such as the Sea of Okhotsk, and the Yellow and East China Seas, are characterized by strong tidal activity, making tidal mixing a crucial factor in the variability of regional stratification and water mass properties. To investigate tidal effects on oceanic circulation in the subpolar region of the North Pacific, we present an eddy-permitting (1/4°) nested ocean model for the Northwestern Pacific region interacting with the global ocean. The ocean component is based on NEMO version 5 with a global horizontal resolution of 0.5°(ORCA05) and applies the two-way nesting method AGRIF for the Northwestern Pacific region (105°–155°E, 15°–60°N); the vertical grid consists of 46 z-star levels. Astronomical tidal forcing was applied by prescribing four major tidal constituents (M2, S2, K1, O1) at the surface boundary. We evaluate model performance by comparison with observational data. We further analyze key climate variables and upper-ocean states, focusing on the characteristics of the subpolar ocean circulation, such as the Oyashio Current, in the Northwestern Pacific region.
 

Tide,North Pacific,OGCM,Oyashio,subpolar