Quasi-Realistic Model Simulations of Hybrid Kelvin-Edge Waves in the Bay Of Biscay

Harpreet Kaur1, Maarten C Buijsman2, Chan-Hoo Jeon1 and Alexander E Yankovsky3, (1)University of Southern Mississippi, Stennis Space Center, MS, United States, (2)University of Southern Mississippi, Division of Marine Science, Stennis Space Center, MS, United States, (3)University of South Carolina Columbia, Columbia, SC, United States
Abstract:
In this study, we investigate the scattering process of semidiurnal hybrid Kelvin-edge waves along widening shelves using quasi-realistic model simulations. Kelvin waves on continental shelves may convert to hybrid Kelvin-edge (HKE) waves and internal waves due to the change in continental shelf width. In this process the group velocity reaches a minimum and tidal energy is radiated on and/or offshore (Zhang and Yankovsky, 2016). This scattering has been found to occur in idealized model studies (Zhang and Yankovsky, 2016; Yankovsky and Zhang, 2017). Our objective is to characterize the HKE wave transition for the Bay of Biscay. The Bay of Biscay features a continental shelf that widens in the propagation (downstream) direction and an alongshore flux that changes its direction perpendicular to the coast. Strong internal wave generation is also observed in this region. It is not clear how the complex realistic bathymetry of the Bay of Biscay affects the HKE scattering process. Hence we perform quasi-realistic 1/25⁰ barotropic Hybrid Coordinate Ocean Model (HYCOM) simulations of the Bay of Biscay/Celtic sea, in which the realistic bathymetry is gradually changed to a more idealized bathymetry. These regional simulations are one-way nested in global tide simulations by Jeon et al (2019). In a series of experiments, the deep ocean is made flat with depth of 4000 m, the English and St. Georges channels are closed and the coastline is extended seaward. In a final simulation, the bathymetry has been changed to reflect the idealized configuration of Yankovsky and Zhang (2017). In preliminary results we find that the flux patterns begin to resemble the results by Yankovsky and Zhang (2017). The modified bathymetry causes an offshore flux where the shelf widens, which suggests a HKE wave transition.

Bibliography

Jeon, C.-H., M. Buijsman, A. J. Wallcraft, J. F. Shriver, B. K. Arbic, J. G. Richman and P. J. Hogan (2019), Ocean Modelling, 137, 98—113. doi.org/10.1016/j.ocemod.2019.03.007.

Zhang, T., and A. E Yankovsky (2016), J. Geophys. Res. Oceans, 121, 3058–3074. doi:10.1002/2015JC011617.

Yankovsky, A.E. and T. Zhang (2017), J. Phys. Oceanogr., 47, 2545–2562. doi.org/10.1175/JPO-D-16-0284.1

Back to: Ocean Tides: From Planetary to Turbulent Scales III Posters