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4. A unified breaking onset criterion for surface gravity water waves in arbitrary depth

Author

Derakhti, Morteza, Kirby, James T., Banner, Michael L., Grilli, Stephan T., and Thomson, Jim

Subjects
Physics - Fluid Dynamics
Abstract

We investigate the validity and robustness of the Barthelemy et al. (2018) breaking wave onset prediction framework for surface gravity water waves in arbitrary water depth, including shallow water breaking over varying bathymetry. We show that the Barthelemy et al. (2018) breaking onset criterion, which they validated for deep and intermediate water depths, also segregates breaking crests from non-breaking crests in shallow water, with subsequent breaking always following the exceedance of their proposed generic breaking threshold. We consider a number of representative wave types, including regular, irregular, solitary, and focused waves, shoaling over idealized bed topographies including an idealized bar geometry and a mildly- to steeply-sloping planar beach. Our results show that the new breaking onset criterion is capable of detecting single and multiple breaking events in time and space in arbitrary water depth. Further, we show that the new generic criterion provides improved skill for signaling imminent breaking onset, relative to the available kinematic or geometric breaking onset criteria in the literature. In particular, the new criterion is suitable for use in wave-resolving models that cannot intrinsically detect the onset of wave breaking., Comment: 31 pages, 18 figures

Published
2019

7. Validation and inter-comparison of models for landslide tsunami generation

Author

Kirby, James T., Grilli, Stephan T., Horrillo, Juan, Liu, Philip L.-F., Nicolsky, Dmitry, Abadie, Stephane, Ataie-Ashtiani, Behzad, Castro, Manuel J., Clous, Lucie, Escalante, Cipriano, Fine, Isaac, González-Vida, José Manuel, Løvholt, Finn, Lynett, Patrick, Ma, Gangfeng, Macías, Jorge, Ortega, Sergio, Shi, Fengyan, Yavari-Ramshe, Saeedeh, and Zhang, Cheng

Published
2022
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14. Statistics of Bubble Plumes Generated by Breaking Surface Waves.

Author

Derakhti, Morteza, Thomson, Jim, Bassett, Christopher, Malila, Mika, and Kirby, James T.

Subjects
WATER waves, PLUMES (Fluid dynamics), OCEAN waves, UNDERWATER acoustics, WIND speed, WIND measurement, OCEAN-atmosphere interaction
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−1 and 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. Plain Language Summary: Quantifying the statistics of bubble plumes generated during ocean surface wave breaking is essential to understanding the exchange between the ocean and the atmosphere. Bubble plumes also cause important variations in underwater acoustics and optics. Recent studies also suggest that the statistics of bubble plumes are skillful predictors for total energy loss during wave breaking, which is an essential quantity for accurate wave forecasting. In this study, we examine how these bubble plume statistics change with different wind and wave conditions, including during storms. We used echosounders on drifting buoys to detect the bubbles and estimate how deep they go in the ocean. We also used shipboard camera systems to measure the surface area of the bubble plumes. We successfully develop multiple empirical relationships that allow us to predict how bubble plume depth and surface area change as a function of simple wind and wave statistics. These statistics are readily available from existing forecast models or typical ocean buoys. Our findings reveal that bubble plume depth is correlated with its visible surface area. This intriguing correlation suggests that we might estimate the volume of bubble plumes simply by observing the ocean surface from above. Key Points: Bubble plumes generated during ocean surface wave breaking are observed with echosounders on drifting buoysBubble plume depths are well correlated with whitecap coverage, wind speed, and spectral wave steepnessBubble plumes persist for many wave periods and exceed the persistence of visible surface foam [ABSTRACT FROM AUTHOR]

Published
2024
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20. Inter-model analysis of tsunami-induced coastal currents

Author

Lynett, Patrick J., Gately, Kara, Wilson, Rick, Montoya, Luis, Arcas, Diego, Aytore, Betul, Bai, Yefei, Bricker, Jeremy D., Castro, Manuel J., Cheung, Kwok Fai, David, C. Gabriel, Dogan, Gozde Guney, Escalante, Cipriano, González-Vida, José Manuel, Grilli, Stephan T., Heitmann, Troy W., Horrillo, Juan, Kânoğlu, Utku, Kian, Rozita, Kirby, James T., Li, Wenwen, Macías, Jorge, Nicolsky, Dmitry J., Ortega, Sergio, Pampell-Manis, Alyssa, Park, Yong Sung, Roeber, Volker, Sharghivand, Naeimeh, Shelby, Michael, Shi, Fengyan, Tehranirad, Babak, Tolkova, Elena, Thio, Hong Kie, Velioğlu, Deniz, Yalçıner, Ahmet Cevdet, Yamazaki, Yoshiki, Zaytsev, Andrey, and Zhang, Y.J.

Published
2017
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