Introduction

The interactions between winds, waves, and currents are responsible for the exchange of mass, momentum, and heat in the air-sea boundary layer (Villas Bôas and Pizzo 2021). Waves serve as the interface between the atmosphere and ocean, playing a key role in the air-sea fluxes. Understanding the role of waves in these fluxes is essential to better understand the interplay between the atmospheric and oceanic systems of the Earth (Cavaleri et al., 2012).

Wave amplitude, wavelength, and directions are affected by their interactions with wind and currents. The response time for the effects of winds and currents can occur over a broad range of temporal scales (days to hours) and spatial scales (thousands to single kilometers). For example, when an atmospheric storm over the ocean occurs, the sea surface roughens, and wave height increases at the scale of the storm, typically on the order of 1000 kilometers and lasting several days. Although the effects of currents on waves are less intuitive to conceptualize compared to large-scale wind influences, they are nonetheless widely observed. Indeed, currents and their spatial gradients can enhance the wave height (Villas Bôas et al., 2020), wave breaking probability (Vrecica et al., 2021), or deviate waves from a great-circle trajectory (Gallet and Young 2014). Numerical results indicate that currents influence wave properties spatially, extending down to the scale of the current itself (Villas Bôas et al., 2020).

Observations of the effects of winds and currents on waves have been primarily focused on wave height because of satellites making global scale observations of this variable more convenient (Ardhuin et al., 2019). These observations, however, are typically restricted to basin scale down to small mesoscale ranges (1000-30 km) because of satellite measurement limitations (Ardhuin et al., 2017). Outside of the limitations in observing changes of wave height at scales below 30 km, the lack of co-located, high resolution wind and current data restricts the complete interpretation and characterization of these changes and the associated air-sea fluxes. As there is evidence of submesoscale currents in both in-situ and satellite observations (McWilliams 2016), there is good reason to assume that they may affect wave quantities at the same scales, however sampling submesoscale currents is very challenging because of their spatio-temporal scales (hours to one day, <30 km).

In the SUB-MESOSCALE OCEAN DYNAMICS EXPERIMENT (SMODE), Saildrones were used to collect colocalized current, wind, and wave observations along their trajectories. A library of fronts was identified to provide an insight into the three-way coupling between currents, winds, and waves in the submesoscale.

This analysis utilizes co-located Saildrone observations to investigate how variations in winds and currents influence wave characteristics.