Diapycnal mixing in the Brazil-Malvinas confluence front
dc.contributor.author
dc.date.accessioned
2023-02-15T13:11:31Z
dc.date.available
2023-02-15T13:11:31Z
dc.date.issued
2023-02
dc.identifier.issn
0079-6611
dc.identifier.uri
dc.description.abstract
Diapycnal mixing in the Brazil-Malvinas Confluence Zone (BMC) is assessed on the basis of microstructure measurements done as part of an April 2017 cruise, which explored the mesoscalar and regional frontal dynamics. Sampling was done down to 400 m in 11 locations on both sides of the BMC, over the slope and in the abyssal waters. Turbulent scales, non-dimensional numbers, energy dissipation rates and diapycnal eddy diffusivities are calculated, which allow us to assess the state of the small-scale turbulence in the frontal region.
Active turbulence was present at all depths and stations, with high-dissipation patches ranging from several metres to a few tens of metres. The frontal zone is characterized by high energy dissipation and eddy diffusivity. The geometric mean eddy diffusivity for all stations and the entire water column is 7.0 × 10-4 m2 s−1. The mean values halve when only considering the more stratified seasonal thermocline, 3.8 × 10-4 m2 s−1, and are twice larger south than north of the BMC.
High dissipation rates coincide with high vertical shear, possibly related to the convergence of the two intense currents and/or the generation of internal waves by the associated mesoscalar and submesoscalar features. The layered structures related to intruding filaments favor double diffusive convection and salt fingering. Near-bottom mixing at the stations on the continental slope is possible related to shear-driven Kelvin-Helmoltz instabilities
dc.description.sponsorship
We are very grateful to the crew of R/V Hespérides for his support during the RETRO-BMC cruise. This study has been supported by the Spanish Government through projects VA-DE-RETRO (CTM2014-56987-P) and SAGA (RTI2018-100844-B-C33)
Open Access funding provided thanks to the CRUE-CSIC agreement with Elsevier
dc.format.mimetype
application/pdf
dc.language.iso
eng
dc.publisher
Elsevier
dc.relation.isformatof
Reproducció digital del document publicat a: https://doi.org/10.1016/j.pocean.2023.102968
dc.relation.ispartof
Progress in Oceanography, 2023, vol. 211, art. núm. 102968
dc.relation.ispartofseries
Articles publicats (D-F)
dc.rights
Attribution 4.0 International
dc.rights.uri
dc.subject
dc.title
Diapycnal mixing in the Brazil-Malvinas confluence front
dc.type
info:eu-repo/semantics/article
dc.rights.accessRights
info:eu-repo/semantics/openAccess
dc.type.version
info:eu-repo/semantics/publishedVersion
dc.identifier.doi
dc.type.peerreviewed
peer-reviewed
dc.identifier.eissn
1873-4472
dc.description.ods
14. Life Below Water