Contribution of Sea-State Dependent Bubbles to Air-Sea Carbon Dioxide Fluxes

Breaking surface ocean waves produce bubbles that are important for air-sea gas exchanges, particularly during high winds. In this study we estimate air-sea CO2 fluxes globally using a new approach that directly considers the sea-state (surface wave) dependent contribution to the gas fluxes. We estimate that 40% of the total air-sea CO2 flux is via bubbles, with yearly, seasonal, and regional variability. When compared to the traditional gas-flux parameterization method that considers the wind speed alone, we find high-frequency (daily to weekly) differences in the predicted gas flux using the sea-state dependent method at spatial scales related to atmospheric weather (10 to 100km). Seasonal differences in the air-sea CO2 flux between the two methods range from 20 to 60%, with the largest values associated with winter storms. These results confirm that bubbles are important for global gas-flux dynamics and that sea-state dependent parameterizations may improve performance of global coupled models.