Search for: All records

Surface waves are important for remote sensing, air–sea exchange, and underwater acoustics. The short gravity wave spectrum is azimuthally broad and bimodal. However, widely used wave models fail to reproduce the degree of observed spreading and azimuthal bimodality. Recent studies show that an azimuthally narrow spectral breaking dissipation due to long‐wave short‐wave modulation significantly improves model performance, highlighting the importance of better understanding the directionality of breaking kinematics. We utilized visible stereo imagery to investigate the directional wave‐breaking kinematics relative to the energy spectrum under aligned and misaligned winds and dominant waves. The results show that the statistical distribution of wave‐breaking kinematics closely aligns with the direction of the dominant waves and is azimuthally unimodal and narrower than the bimodal energy spectrum. These findings confirm the importance of exploring the directionality of breaking to improve our understanding of the spectral energy balance and spectral wave models within the short‐gravity range. 

The air–sea exchange of carbon dioxide (CO2) on a global scale is a key factor in understanding climate change and predicting its effects. The magnitude of sea spray’s contribution to this flux is currently highly uncertain. Constraining CO2’s diffusion in sea spray droplets is important for reducing error margins in global estimates of oceanic CO2 uptake and release. The timescale for CO2 gas diffusion within sea spray is known to be shorter than the timescales for the droplets’ physical changes to take place while aloft. However, the rate of aqueous carbonate reactions relative to these timescales has not been assessed. This study investigates the timescales of droplet physical changes to those of chemical transformations across the H2CO3/HCO3−/CO32− sequence. We found that physical timescales are rate limiting and that evaporation drives carbonate species into gaseous CO2, promoting the production and evasion of CO2 from sea spray droplets. This has important implications for carbon cycling and feedback in the surface ocean.