Effect of small-scale topography on eddy dissipation in the Northern South China Sea

Zhibin Yang (Lead Author), Zhao Jing, Xiaoming Zhai

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Abstract

Mesoscale eddies are ubiquitous dynamical features, accounting for over 90% of 33 the total kinetic energy of the ocean. However, the pathway for eddy energy 34 dissipation has not been fully understood. Here we investigate the effect of 35 small-scale topography on eddy dissipation in the northern South China Sea by 36 comparing high-resolution ocean simulations with smooth and synthetically-generated 37 rough topography. The presence of rough topography is found to (1) significantly 38 enhance viscous dissipation and instabilities within a few hundred meters above the 39 rough bottom, especially in the slope region, and (2) change the relative importance of 40 energy dissipation by bottom frictional drag and interior viscosity. The role of lee 41 wave generation in eddy energy dissipation is investigated using a Lagrangian filter 42 method. About one-third of the enhanced viscous energy dissipation in the rough 43 topography experiment is associated with lee wave energy dissipation, with the 44 remaining two-thirds explained by nonwave energy dissipation, at least partly as a 45 result of the nonpropagating form drag effect.
Original languageEnglish
JournalJournal of Physical Oceanography
Publication statusAccepted/In press - 10 Jun 2022

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