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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.
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Solitary Waves Impinging on an Isolated Tropical Reef: Arrival Patterns and Wave Transformation Under Shoaling
Abstract Large nonlinear internal solitary waves (NLIWs) are known to transit west northwest across the northeastern South China Sea from generation sites around the two‐ridge system in the Luzon Strait. The waves are important because their energy flux and dissipation are several orders of magnitude larger than the surrounding ocean. The wave transit has been well studied up to about the 100 m isobath but observations in shallower water have been scarce. Using oceanographic moorings and an innovative distributed temperature sensing optical cable, the NLIW transformations were observed from 2000 to 2 m on the flanks of Dongsha Atoll (Pratas Reef). Possible outcomes included reflection, refraction around the island, wave breaking, and penetration into shallow water. Upslope penetration depended on incident wave amplitude and direction as well as the local stratification.
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- Award ID(s):
- 1753317
- PAR ID:
- 10408346
- Publisher / Repository:
- DOI PREFIX: 10.1029
- Date Published:
- Journal Name:
- Journal of Geophysical Research: Oceans
- Volume:
- 127
- Issue:
- 3
- ISSN:
- 2169-9275
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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