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How important are diapycnal mixing and geothermal heating for the deep circulation of the Western Mediterranean?
Author(s) -
Ferron B.,
Bouruet Aubertot P.,
Cuypers Y.,
Schroeder K.,
Borghini M.
Publication year - 2017
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1002/2017gl074169
Subject(s) - buoyancy , turbulence , neutral buoyancy , geothermal gradient , geology , mixing (physics) , dissipation , oceanography , environmental science , atmospheric sciences , meteorology , geography , mechanics , geophysics , physics , thermodynamics , quantum mechanics
The dissipation rate of turbulent kinetic energy ε and the associated diapycnal turbulent mixing is inferred from a set of microstructure observations collected over several cruises from year 2012 to 2014. The geographical distribution of ε highlights several regions of enhanced levels of turbulence ranging from 10 −9 to 10 −6 W kg −1 : the Sicily Channel, the Corsica Channel, and the Ligurian Sea. Elsewhere, ε was small, often below 10 −10 W kg −1 . Below 1300 m, geothermal heating provides three‐fold more buoyancy than small‐scale turbulence. Geothermal heating and turbulent diffusion provide enough buoyancy to balance 15% to 50% of a mean yearly deep water formation rate of 0.9 to 0.3 sverdrup (10 6 m 3 /s), respectively. The remaining part has to eventually overflow through the Strait of Gibraltar.