FN Archimer Export Format
PT J
TI Contribution of Thermohaline Staircases to Deep Water Mass Modifications in the Western Mediterranean Sea From Microstructure Observations
BT 
AF Ferron, Bruno
   Bouruet-Aubertot, Pascale
   Schroeder, Katrin
   Bryden, Harry L.
   Cuypers, Yannis
   Borghini, Mireno
AS 1:1;2:2;3:3;4:4;5:2;6:5;
FF 1:;2:;3:;4:;5:;6:;
C1 Laboratoire d’Océanographie Physique et Spatiale, Univ Brest-CNRS-IFREMER-IRD-IUEM, Brest, France
   Sorbonne Université (UPMC, Univ Paris 06)-CNRS-IRD-MNHN, LOCEAN, Paris, France
   Consiglio Nazionale delle Ricerche – Istituto di Scienze Marine (CNR-ISMAR), Venice, Italy
   Ocean and Earth Science, University of Southampton, Southampton, United Kingdom
   Consiglio Nazionale delle Ricerche – Istituto di Scienze Marine (CNR-ISMAR), Lerici, Italy
C2 CNRS, FRANCE
   UNIV SORBONNE, FRANCE
   CNR ISMAR, ITALY
   UNIV SOUTHAMPTON, UK
   CNR ISMAR, ITALY
UM LOPS
IN WOS Cotutelle UMR
   DOAJ
   copubli-france
   copubli-europe
   copubli-univ-france
IF 5.247
TC 4
UR https://archimer.ifremer.fr/doc/00694/80624/83893.pdf
LA English
DT Article
DE ;microstructure;double-diffusion;staircases;Mediterranean basin;turbulence;salt-fingering;upwelling;mixing
AB Recent observations from profiles of temperature and salinity in the Algerian Sea showed that salt finger mixing can significantly warm and salinify the deep waters within a period of 2 years, thereby contributing to the erosion of deep water properties formed during winter convection episodes. In this study, heat, salt, and buoyancy fluxes associated with thermohaline staircases are estimated using microstructure observations from four locations of the Western Mediterranean Sea: The Tyrrhenian Sea, the Algerian Sea, the Sardino-Balearic Sea, and the Ligurian Sea. Those fluxes are compared to the rare estimates found in the Mediterranean Sea. Microstructure data show that the temperature variance dissipation rate is one to three orders of magnitude larger in the strong steps that separate weakly stratified layers than in the layers, while the turbulent kinetic energy dissipation rate remains usually weak both in steps and layers. In the steps, the turbulent eddy diffusivity of salt is on average twice as large as that of temperature. The buoyancy flux ratio decreases with the density ratio. It is found that staircases induce a downward heat transfer rate of 46 to 103 × 109 W over the whole western basin, and a downward salt transfer rate of 4.5 to 10.3 × 103 kg s–1 between 1000 and 2000 m. This heat convergence is 2–5 times as large as the western Mediterranean geothermal heat flux in this depth range. Over the whole western basin, heat and salt convergences from salt-fingering staircases are 50% to 100% of those generated by mechanical mixing. Finally, it is found that heat and salt convergences from geothermal heating, salt-fingering and mechanical mixing can balance a deep water upwelling of 0.4 × 106 m3 s–1. 
PY 2021
PD MAY
SO Frontiers In Marine Science
SN 2296-7745
PU Frontiers Media SA
VL 8
UT 000655654100001
DI 10.3389/fmars.2021.664509
ID 80624
ER

EF