Contributions by speaker > De Lavergne Casimir

Is the abyssal overturning driven by breaking internal waves?
Casimir De Lavergne  1@  , Gurvan Madec  2@  , Julien Le Sommer, George Nurser, Alberto Naveira Garabato@
1 : Laboratoire d'Océanographie et du Climat : Expérimentations et Approches Numériques  (LOCEAN)
Museum National d'Histoire Naturelle, INSU, CNRS : UMR7159, Université Pierre et Marie Curie - Paris VI
case 100 4 place jussieu 75252 PARIS CEDEX 05 -  France
2 : Laboratoire d'Océanographie et du Climat : Expérimentations et Approches Numériques  (LOCEAN)
Museum National d'Histoire Naturelle : USM402, INSU, CNRS : UMR7159, Université Pierre et Marie Curie - Paris VI
case 100 4 place jussieu 75252 PARIS CEDEX 05 -  France

At steady state, Antarctic Bottom Water (AABW) must be consumed in the ocean interior at the same rate it is produced around Antarctica. To understand how and where this consumption is achieved, we estimate deep water mass transformation by internal wave-driven mixing and geothermal heating. Using parameterizations of lee wave and internal tide energy dissipation combined with two different models for the mixing efficiency, we show that near-field mixing by breaking internal tides and lee waves cannot account for the full strength of the abyssal overturning, inducing only ~ 4 Sv of AABW upwelling north of 30ºS. This is comparable to the ~ 5 Sv of AABW upwelling caused by geothermal heating. The possible role of remotely-dissipating internal tides in complementing AABW consumption is explored.



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