The Northwest Pacific Ocean is one of the most important oceanic carbon sink regions in the global carbon cycle, accounting for a substantial fraction of the oceanic uptake of anthropogenic carbon dioxide (CO₂). Air–sea CO₂ exchange in this region is jointly regulated by the Kuroshio and Kuroshio Extension systems, mesoscale ocean dynamics, biological production, carbonate chemistry, and large-scale climate variability. Under future climate change, however, ocean warming, enhanced upper-ocean stratification, changes in atmospheric circulation, and modifications of ocean currents are expected to alter the regional carbon cycle significantly. Despite considerable progress in Earth system modeling, substantial uncertainties remain regarding the future evolution of the Northwest Pacific carbon sink, particularly the mechanisms controlling its spatial redistribution and the role of high-resolution ocean processes.

This study aims to investigate the future evolution of air–sea CO₂ fluxes and ocean carbon uptake in the Northwest Pacific using a high-resolution physical–biogeochemical coupled modeling framework. A regional ocean model coupled with a marine biogeochemical model will be driven by statistically downscaled future atmospheric forcing to better resolve regional circulation, mesoscale variability, and coastal–open ocean interactions. Future simulations under multiple climate scenarios will be conducted to characterize the spatial and temporal evolution of the regional carbon sink throughout the twenty-first century.

The study will focus on three major scientific objectives. First, it will quantify the long-term changes and spatial redistribution of air–sea CO₂ fluxes under future climate conditions, with particular attention to the Kuroshio Extension and adjacent waters. Second, it will identify the dominant drivers of future carbon sink variability by separating the contributions of sea surface temperature, wind speed, air–sea CO₂ partial pressure difference, dissolved inorganic carbon, alkalinity, and biological production. Third, it will investigate how mesoscale ocean dynamics, upper-ocean mixing, and biological–physical interactions regulate future carbon uptake and evaluate the added value of high-resolution modeling relative to coarse-resolution climate models.

By integrating atmospheric downscaling, high-resolution ocean circulation, and marine biogeochemical simulations, this study is expected to improve the understanding of the mechanisms governing future carbon sink evolution in the Northwest Pacific. The results will provide new insights into the coupled physical and biogeochemical processes controlling regional air–sea CO₂ exchange, reduce uncertainties in regional carbon budget projections, and contribute to improving future climate prediction and global carbon cycle assessments.