More Like this

1. Three‐Dimensional Measurements of Air Entrainment and Enhanced Bubble Transport During Wave Breaking

   https://doi.org/10.1029/2022GL099436  

   Ruth, Daniel J.; Néel, Baptiste; Erinin, Martin A.; Mazzatenta, Megan; Jaquette, Robert; Veron, Fabrice; Deike, Luc (August 2022, Geophysical Research Letters)
2. Secondary Gravity Waves Generated by Breaking Mountain Waves Over Europe

   https://doi.org/10.1029/2019JD031662  

   Heale, C. J.; Bossert, K.; Vadas, S. L.; Hoffmann, L.; Dörnbrack, A.; Stober, G.; Snively, J. B.; Jacobi, C. (March 2020, Journal of Geophysical Research: Atmospheres)
3. Moist heatwaves intensified by entrainment of dry air that limits deep convection

   https://doi.org/10.1038/s41561-024-01498-y  

   Duan, Suqin Q; Ahmed, Fiaz; Neelin, J David (July 2024, Nature Geoscience)

   Moist heatwaves in the tropics and subtropics pose substantial risks to society, yet the dynamics governing their intensity are not fully understood. The onset of deep convection arising from hot, moist near-surface air has been thought to limit the magnitude of moist heatwaves. Here we use reanalysis data, output from the Coupled Model Intercomparison Project Phase 6 and model entrainment perturbation experiments to show that entrainment of unsaturated air in the lower-free troposphere (roughly 1–3 km above the surface) limits deep convection, thereby allowing much higher near-surface moist heat. Regions with large-scale subsidence and a dry lower-free troposphere, such as coastal areas adjacent to hot and arid land, are thus particularly susceptible to moist heatwaves. Even in convective regions such as the northern Indian Plain, Southeast Asia and interior South America, the lower-free tropospheric dryness strongly afects the maximum surface wet-bulb temperature. As the climate warms, the dryness (relative to saturation) of the lower-free tropospheric air increases and this allows for a larger increase of extreme moist heat, further elevating the likelihood of moist heatwaves. 

   more » « less
4. Laboratory studies of Lagrangian transport by breaking surface waves

   https://doi.org/10.1017/jfm.2019.544  

   Lenain, Luc; Pizzo, Nick; Melville, W. Kendall (October 2019, Journal of Fluid Mechanics)

   While it has long been recognized that Lagrangian drift at the ocean surface plays a critical role in the kinematics and dynamics of upper ocean processes, only recently has the contribution of wave breaking to this drift begun to be investigated through direct numerical simulations (Deike et al. ,  J. Fluid Mech. , vol. 829, 2017, pp. 364–391; Pizzo et al. ,  J. Phys. Oceanogr. , vol. 49(4), 2019, pp. 983–992). In this work, laboratory measurements of the surface Lagrangian transport due to focusing deep-water non-breaking and breaking waves are presented. It is found that wave breaking greatly enhances mass transport, compared to non-breaking focusing wave packets. These results are in agreement with the direct numerical simulations of Deike  et al. ( J. Fluid Mech. , vol. 829, 2017, pp. 364–391), and the increased transport due to breaking agrees with their scaling argument. In particular, the transport at the surface scales with $$S$$ , the linear prediction of the maximum slope at focusing, while the surface transport due to non-breaking waves scales with $$S^{2}$$ , in agreement with the classical Stokes prediction. 

   more » « less
5. Statistics of Bubble Plumes Generated by Breaking Surface Waves

   https://doi.org/10.1029/2023JC019753  

   Derakhti, Morteza; Thomson, Jim; Bassett, Christopher; Malila, Mika; Kirby, James T (May 2024, Journal of Geophysical Research: Oceans)

   Abstract We examine the dependence of the penetration depth and fractional surface area (e.g., whitecap coverage) of bubble plumes generated by breaking surface waves on various wind and wave parameters over a wide range of sea state conditions in the North Pacific Ocean, including storms with sustained winds up to 22 m s⁻¹and significant wave heights up to 10 m. Our observations include arrays of freely drifting SWIFT buoys together with shipboard systems, which enabled concurrent high‐resolution measurements of wind, waves, bubble plumes, and turbulence. We estimate bubble plume penetration depth from echograms extending to depths of more than 30 m in a surface‐following reference frame collected by downward‐looking echosounders integrated onboard the buoys. Our observations indicate that mean and maximum bubble plume penetration depths exceed 10 and 30 m beneath the surface during high winds, respectively, with plume residence times of many wave periods. They also establish strong correlations between bubble plume depths and wind speeds, spectral wave steepness, and whitecap coverage. Interestingly, we observe a robust linear correlation between plume depths, when scaled by the total significant wave height, and the inverse of wave age. However, scaled plume depths exhibit non‐monotonic variations with increasing wind speeds. Additionally, we explore the dependencies of the combined observations on various non‐dimensional predictors used for whitecap coverage estimation. This study provides the first field evidence of a direct relation between bubble plume penetration depth and whitecap coverage, suggesting that the volume of bubble plumes could be estimated by remote sensing. 

   more » « less