South China Sea is the largest marginal sea in the northwestern Pacific, exchanges water with the open Pacific through the Luzon Strait. Its ventilation processes can therefore influence the transport and storage of anthropogenic carbon within the marginal-sea interior. To quantify the anthropogenic carbon storage and ventilation mechanisms in the South China Sea in 2022, we present the first shipboard CFC-12 and SF₆ measurements from the NORC cruise. Using these dual-transient tracers alongside hydrographic data, we apply the Transit Time Distribution (TTD) method to constrain ventilation ages, thereby estimating anthropogenic carbon storage concentrations and stratified column inventories. Compared with a single-tracer approach, the different atmospheric histories of CFC-12 and SF₆ allow the mean age and width of the TTD to be constrained simultaneously within their applicable range, thereby reducing uncertainties associated with prescribed TTD parameter assumptions. The results show that the 0-1000 m anthropogenic carbon inventory in the South China Sea was approximately 30.8 mol C m^-2 in 2022. Layer inventories were 8.21, 9.98, 7.72, and 4.89 mol C m^-2 for 0-100 m, 100-300 m, 300-600 m, and 600-1000 m, respectively. The 100-300 m layer contained the largest inventory, indicating that recent anthropogenic carbon signals were not confined to the surface layer but were transported into the ocean interior through subsurface waters. The subsurface salinity maximum observed in this layer further suggests that anthropogenic carbon signals can enter the South China Sea with northwestern Pacific subsurface waters. Below 300 m, anthropogenic carbon inventories decreased with depth, reflecting the attenuation of recent anthropogenic signals as ventilation times increased. These results indicate that the 2022 vertical distribution of anthropogenic carbon in the South China Sea was jointly regulated by air-sea exchange, Pacific lateral input, subsurface ventilation, and interior mixing.
 

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