Internal Wave Momentum Fluxes at Kaena Ridge, Hawaii
Abstract
Internal waves are effective agents for the vertical transport of horizontal momentum. At frequencies above inertial, wave vertical and horizontal velocity perturbations are in-phase, leading to large Reynolds stresses. Such stresses should be measurable at sites of anisotropic wave propagation. At Kaena Ridge, Hawaii, tidally generated waves radiate offshore, normal to the azimuth of the ridge. Observations from the Research Platform FLIP in the 2002 Home Nearfield Experiment identify fluxes of order 10-4 m2/s2 associated with baroclinic semidiurnal waves. The waves have large vertical scale, λz ~ 2km. Subtle variation in the phase of vertical and horizontal velocity fields leads to depth-localized stress profiles. Time-averaged profiles rotate counter clockwise (viewed from above) with increasing altitude above the 1100m ridge crest. Profiles averaged over individual spring and neap tides exhibit similar structure. Momentum flux is reduced by a factor of ~ 3 during neap tides.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2008
- Bibcode:
- 2008AGUFMOS53E1384P
- Keywords:
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- 4500 OCEANOGRAPHY: PHYSICAL;
- 4544 Internal and inertial waves;
- 4568 Turbulence;
- diffusion;
- and mixing processes (4490)