Development of a Mesoscale- and Tide-Resolving Ocean-Biogeochemistry Model for the Pacific: Tidal Enhancement of the Biological Carbon Pump

This study presents a new physical-biogeochemical simulation of the Pacific Ocean that resolves mesoscale dynamics and explicitly includes tidal forcing. The primary objective is to develop and document a modeling framework that serves both as a detailed record of model configuration and forcing preparation, and as a reference for future regional downscaling. The model is extensively evaluated against physical and biogeochemical datasets and successfully reproduces large-scale circulation patterns and key biogeochemical features. The second objective is to assess the impact of explicitly including tidal forcing on primary production and carbon export, thereby clarifying the biogeochemical consequences of tidal dynamics. While tides are known to energize high-frequency motions, their influence on ocean biogeochemistry remains insufficiently constrained. By comparing simulations with and without tidal forcing, we show that tides enhance net primary production and particulate organic carbon export, particularly in coastal zones and the eastern equatorial Pacific. Basin-wide, tidal forcing increases carbon uptake by approximately 0.45 PgC yr-1 and export by 0.09 PgC yr-1. This enhancement is primarily driven by tide-induced mixing, which increases nutrient supply to the surface and stimulates biological productivity. These findings underscore the importance of accounting for tidal processes in ocean biogeochemical models to improve estimates of the global carbon cycle and refine projections of future oceanic carbon uptake.