Significant dissipation of tidal energy in the deep ocean inferred from satellite altimeter data

Publication Type Journal Article
Year 2000
Journal Nature
Primary Author Egbert, G. D.
Author Ray, R. D.
Volume 405
Issue 6788
Pages 775-558
DOI 10.1038/35015531
Abstract How and where the ocean tides dissipate their energy are long-standing questions1 that have consequences ranging from the history of the Moon2 to the mixing of the oceans3. Historically, the principal sink of tidal energy has been thought to be bottom friction in shallow seas4, 5. There has long been suggestive evidence6, 7, however, that tidal dissipation also occurs in the open ocean through the scattering by ocean-bottom topography of surface tides into internal waves, but estimates of the magnitude of this possible sink have varied widely3, 8, 9, 10, 11. Here we use satellite altimeter data from Topex/Poseidon to map empirically the tidal energy dissipation. We show that approximately 1012 watts—that is, 1 TW, representing 25–30% of the total dissipation—occurs in the deep ocean, generally near areas of rough topography. Of the estimated 2 TW of mixing energy required to maintain the large-scale thermohaline circulation of the ocean12, one-half could therefore be provided by the tides, with the other half coming from action13 on the surface of the ocean.
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