Abstract
Internal tides generated by a rough sea floor are an important source of mixing in the abyssal ocean. Two linear models are employed to evaluate the conversion rate from barotropic tides to internal tides and the energy distribution in each mode. Considering the periodicity of internal tides, the topography is represented by periodically distributed knife edges and sinusoidal ridges within one wavelength of mode-1 internal tides. The knife edges generate greater internal tides than the sinusoidal ridges due to their sharp shape, which approximates an extremely supercritical condition. Energy flux concentrates in modes whose numbers are multiples of the knife edge or ridge number. Then, a fully nonlinear model that integrates viscosity and diffusion is implemented, and its results are compared with those of the linear model. Internal wave rays generated in the nonlinear model show a distribution similar to the linear models’ prediction. High dissipation rates coincide with the rays, suggesting that nonlinear wave-wave interaction is a dominant mechanism for internal tide dissipation in the abyssal ocean.
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Acknowledgements
The helpful discussions with Drs. Samuel Kelly and John Huthnance are greatly appreciated. Comments and suggestions from two anonymous reviewers have greatly improved the manuscript. This work was supported by the Project of State Key Laboratory of Satellite Ocean Environment Dynamics, Second Institute of Oceanography (No. SOEDZZ1701), the Youth Visiting ‘Ocean-Star Scholarship’ of the State Key Laboratory of Satellite Ocean Environment Dynamics (No. QNHX1602) and National Key R&D Program of China (No. 2017YFC0305900). We gratefully acknowledge the support of NSFC-41576008 and CXZZ20140521161827690. Numerical computation is supported by the Special Program for Applied Research on Super Computation of the NSFC-Guangdong Joint Fund (No. U1501501).
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Li, Q., Mao, X., Deng, G. et al. Internal Tide Generation and Dissipation by Small Periodic Topography in Deep Ocean. J. Ocean Univ. China 18, 761–770 (2019). https://doi.org/10.1007/s11802-019-3966-7
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DOI: https://doi.org/10.1007/s11802-019-3966-7