Disentangling Fine-Scale Wind and Current Contributions to Wave Height and Wave Steepness Gradients in the Gulf Stream Region

The combined effects of fine‐scale wind—arising from air–sea coupling and intrinsic atmospheric dynamics—and current on sea states remain poorly understood, largely due to the scarcity of wave‐model analyses forced with high‐resolution coupled winds. We analyzed two coupled ocean–wave-atmosphere simulations in the Gulf Stream region: one included all interaction loops, the other without current effects on waves. Eddy composite analyses of significant wave height (Hₛ), combined with theory, show that currents dominate Hₛ gradients through the current‐induced Doppler shift, overshadowing fine‐scale wind effects for wind‐dependent and wind‐independent wave systems. We extend the analysis to the mean square slope ($mss$), a higher‐order moment of the wave spectrum, sensitive to wind. When current effects on waves are included, $mss$ gradients in the composite eddy are stronger; however, the gradient‐intensity difference between simulations is smaller than for Hₛ. These results have implications for wave representation in climate models and enhancing wind retrieval from space.