Wave Responses and Feedbacks Modulated Air‐Sea Energy Transfer Under Concentric Eyewalls of Typhoon Sinlaku (2008)

Forecasting the intensity and structure of tropical cyclones (TCs) with concentric eyewalls (CEs) is difficult because of their complex structural changes. Secondary eyewall formation (SEF) and eyewall replacement cycles (ERCs) are known to play critical roles in modulating TC evolution. However, how ocean surface wave forcing controls CE dynamics remains poorly quantified. To explore wave distribution and feedback mechanisms under CEs, three sensitivity experiments were designed by reproducing the ERC of Typhoon Sinlaku (2008) using the high‐resolution Coupled Ocean‐Atmosphere‐Wave‐Sediment Transport (COAWST) Modeling System. Numerical simulations revealed that nonlinear wave interactions concentrated significant wave height maxima in the moat region ahead of the TC. Elevated wave energy maintained high sea surface roughness and enthalpy exchange coefficients, even in weak‐wind areas such as the eye and the moat, facilitating ocean wave energy delivery to the inner eyewall, thereby delaying its collapse and extending the ERC duration by approximately two times. In the wave‐coupled simulation, prolonged oceanic enthalpy heat flux maintained inner‐eyewall convection despite weakening tangential winds, in contrast to wave‐uncoupled simulations in which inner collapse was correlated with dry‐air intrusion. The results highlight surface waves as active regulators in sustaining CE structure through localized air‐sea flux modulation, which offer a new insight into improving operational forecasts of TC structural changes via fully coupled air‐sea‐wave modeling.