A Global Eddy-Resolving Coupled Physical-Biological Model: Physical Influences on a Marine Ecosystem in the North Pacific

Abstract

Physical influences on a marine ecosystem in the open ocean are investigated using a simplified four-component ecosystem model embedded in an eddy-resolving ocean general-circulation model (OGCM). The annual cycle of temperature, nitrate, and phytoplankton in the upper ocean is well reproduced with the climatological monthly mean forcing.A comparison with satellite ocean color data shows that the model is capable of a realistic description of the annual mean and regional patterns of surface chlorophyll.Simulated chlorophyll distribution at the surface shows a pattern influenced by the western boundary current (Kuroshio) and meso-scale eddies.Nitrate distribution in the upper ocean in the northwestern Pacific is mainly controlled by physical processes, especially meso-scale variability, including many anticyclonic and cyclonic eddies, fine-scale fronts, and filaments.The warm-core eddy entrains high-nitrate water from the surrounding filaments, creating conditions for the high production in spring.