- Alford, Matthew H.
- Nash, Jonathan D.
- Farmer, David
- Klymak, Jody M.
- Legg, Sonya
- Park, Jae-Hun
- Pickering, Andy
- Simmons, Harper
- MacKinnon, Jennifer A.
- Buijsman, Maarten C.
|Abstract or Summary
- The three-dimensional (3D) double-ridge internal tide interference in the Luzon Strait in the South China
Sea is examined by comparing 3D and two-dimensional (2D) realistic simulations. Both the 3D simulations
and observations indicate the presence of 3D first-mode (semi)diurnal standing waves in the 3.6-km-deep
trench in the strait. As in an earlier 2D study, barotropic-to-baroclinic energy conversion, flux divergence, and
dissipation are greatly enhanced when semidiurnal tides dominate relative to periods dominated by diurnal
tides. The resonance in the 3D simulation is several times stronger than in the 2D simulations for the central
strait. Idealized experiments indicate that, in addition to ridge height, the resonance is only a function of
separation distance and not of the along-ridge length; that is, the enhanced resonance in 3D is not caused by
3D standing waves or basin modes. Instead, the difference in resonance between the 2D and 3D simulations is
attributed to the topographic blocking of the barotropic flow by the 3D ridges, affecting wave generation, and
a more constructive phasing between the remotely generated internal waves, arriving under oblique angles,
and the barotropic tide. Most of the resonance occurs for the first mode. The contribution of the higher modes
is reduced because of 3D radiation, multiple generation sites, scattering, and a rapid decay in amplitude away
from the ridge.
- Buijsman, M. C., Klymak, J. M., Legg, S., Alford, M. H., Farmer, D., MacKinnon, J. A., ... & Simmons, H. (2014). Three-dimensional double-ridge internal tide resonance in Luzon Strait. Journal of Physical Oceanography, 44(3), 850-869. doi:10.1175/JPO-D-13-024.1
|Funding Statement (additional comments about funding)