The Ross Sea is a critical global carbon sink, but spatial differences and interannual mechanisms of carbon sink capacity between its continental shelf (<1000 m) and deep basin (>1000 m) are poorly understood. Based on 2010–2020 growth-season (December–April) outputs from the ROSE model, we validated the model using DIC, sea-surface pco₂ and satellite chlorophyll observations. Divided by the 1000 m isobath, two core questions were explored.Results indicate the deep basin has larger carbon fluxes due to lower sea ice coverage (31% vs. 39%; r=0.887, p<0.001 between flux ratio and open water fraction). Product decomposition distinguishes an ice-controlled regime on the shelf (open water contribution: 62.2%–76.7%) and a wind-biogeochemistry-driven regime in the deep basin (combined contribution of wind and Δpco₂ >80%). The two regions synchronize in weak carbon sink years but diverge during strong sink events. Takahashi decomposition shows biological processes dominate interannual Δpco₂  variability (75%–85%). We further built empirical flux parameterizations (R^2=0.89 for basin, R^2=0.93 for shelf) for regional carbon estimation.