Abstract
Wave breaking modulates air-sea fluxes of energy, momentum, heat, and
gases. Building on recent advances in the modeling of CO2 gas exchange
and wave breaking, we investigate the variability of bubble-mediated gas
transfer coefficients due to wave-current interactions. Submesoscale
current gradients strongly modulate wave breaking, which can enhance the
bubble-mediated gas transfer coefficient by up 80% along temperature
fronts and cold filaments. An empirical scaling based on the mean wave
period, root-mean-square current gradients, and friction velocity can
explain the root-mean-square differences of gas transfer coefficients
computed from solutions with and without current forcing. We also
describe the development of an optimization method to compute the
physics-based model of the bubble-mediated gas transfer coefficient. The
optimization method significantly reduces the computational cost
twentyfold, providing a tractable pathway to investigate air-sea CO2
exchange with coupled models realistically accounting for wave-current
interactions and sea state effects.