Modulation of tropical cyclone intensity by current–wind interaction

Current–wind interaction modulates air–sea momentum and turbulent heat fluxes, which are critical in the energy cycle of tropical cyclones (TCs). However, the effects of the surface currents on air–sea exchange under TCs have remained unclear. Here, using an atmosphere–ocean coupled model, we investigate the role of current–wind interaction in determining TC intensity. Surface currents generally align with surface winds. Accounting for the current–wind interaction, the alignment reduces both the air–sea turbulent heat flux and momentum flux (average 1.0% and 2.5%), which serve as the energy source and sink of TCs, respectively. The reduction in the energy source (sink) decreases (increases) the TC growth −1.9% (+1.3%) on average and up to −13.7% (+11.1%). For simulations extending beyond the seasonal scale, the accumulated impacts of current–wind interaction alter TC genesis, affecting surface wind speed and sea surface temperature during the TC season. These findings reveal an important feedback mechanism associated with TCs driven by the current–wind interaction.