Variability of wind wave field by realistic mesoscale and submesoscale eddy field

Abstract. Recent altimeters and numerical studies have shown that wind waves interact strongly with small scale open ocean currents, and subsequently modify their amplitude, frequency, and direction. In the present paper we investigate the interactions of wind waves with a large realistic cyclonic eddy. This eddy is subject to instabilities leading to the generation of specific features both at mesoscale and submesoscale. We use the WAVEWATCH III framework to force wind waves in the eddy before and after instabilities occurred. Our findings show that the spatial variability of wave direction frequency and amplitude is very sensitive to the presence of underlying submesoscale structures resulting from the eddy destabilisation. As the surface current vorticity, the intrinsic frequency of incident waves is key in the wave response of the current modulation. Our findings also suggest that surface current gradients can be retrieved thanks to wave height gradients at scale where traditional altimeter measurements fail.