Tuesday 23 August 2005

PB3
1000-1220 hours

142
Internal Tide Generation by Seamounts
Baines, Peter¹
1 Dept Of Civil And Environmental Engineering, University of Melbourne, Vic, Australia
Author email: pbaines@unimelb.edu.au
Oceanic internal tides are internal waves of tidal period, generated by advection of the stratified ocean over topography by the barotropic tide, where the latter is forced by the tidal attraction of the moon and sun. They are important because they act as a sink for tidal energy, and may be a significant source of mixing in the deep ocean. Most studies of this generation process have so far concentrated on two-dimensional topographic shapes, such as continental shelf-slopes and mid-ocean ridges. This presentation reports results from generation by flow past seamounts, which are common geological features in mid-ocean, numbered in the thousands for each ocean basin. These indicate that: (i) internal tidal energy generation by seamounts with heights in excess of 1 km exceeds that by continental shelves and slopes; (ii) A large seamount generates more internal tide than a smaller one, but smaller seamounts are more numerous, and collectively contribute more; (iii) In the region where seamounts are concentrated, such as the Western Equatorial Pacific Ocean, the internal tide generated may contribute significantly to vertical mixing.

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