Evidence of double diffusion in the Brazil-Malvinas Confluence
Observation of thermohaline staircases and low-density ratios in the Brazil-Malvinas Confluence (BMC) suggests salt-fingering activity between the high salinity South Atlantic Central Water and low salinity Antarctic Intermediate Water. Vertical salt-finger induced salt fluxes are estimated in the B...
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| Acceso en línea: | http://hdl.handle.net/20.500.12110/paper_09670637_v49_n1_p41_Bianchi |
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todo:paper_09670637_v49_n1_p41_Bianchi2023-10-03T15:55:00Z Evidence of double diffusion in the Brazil-Malvinas Confluence Bianchi, A.A. Piola, A.R. Collino, G.J. Brazil/Malvinas Confluence Double diffusion Mixing Salt finger Southwestern Atlantic Salinity measurement Seawater Thermal diffusion Baroclinicity Oceanography double diffusion fingering salinity vertical mixing water mass Atlantic Ocean Observation of thermohaline staircases and low-density ratios in the Brazil-Malvinas Confluence (BMC) suggests salt-fingering activity between the high salinity South Atlantic Central Water and low salinity Antarctic Intermediate Water. Vertical salt-finger induced salt fluxes are estimated in the BMC using a model for fastest growing fingers. Maximum salt-finger fluxes of 39.9 × 10-10 W kg-1 (5.3 × 10-7 m s-1) were estimated, similar to existing estimates in a Mediterranean salt lens embedded within the North Atlantic water. The fluxes normalized by the large-scale property gradients lead to fairly large estimates of diapycnal haline and thermal diffusivities, of up to 0.74 × 10-4 and 0.34 × 10-4 m2s-1, respectively, showing the enhancement of the haline diffusivity due to salt fingers. Estimated diffusive-convection fluxes based on flux laws derived from laboratory experiments are two orders of magnitude larger than salt-finger fluxes. These results suggest that, where cross-front interleaving leads to layering of relatively cold-fresh water over warm-salty water, diffusive upward convection dominates the vertical property fluxes in the frontal region. It appears that on the warm-salty side of the BMC, away from the narrow band dominated by interleaving, salt-finger integrated vertical fluxes nearly balance the cross-front lateral integrated fluxes. The effect of baroclinicity on the vertical property fluxes was evaluated and it was found that, in the BMC, the baroclinicity enhances the interleaving. © 2001 Elsevier Science Ltd. All rights reserved. JOUR info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by/2.5/ar http://hdl.handle.net/20.500.12110/paper_09670637_v49_n1_p41_Bianchi |
| institution |
Universidad de Buenos Aires |
| institution_str |
I-28 |
| repository_str |
R-134 |
| collection |
Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) |
| topic |
Brazil/Malvinas Confluence Double diffusion Mixing Salt finger Southwestern Atlantic Salinity measurement Seawater Thermal diffusion Baroclinicity Oceanography double diffusion fingering salinity vertical mixing water mass Atlantic Ocean |
| spellingShingle |
Brazil/Malvinas Confluence Double diffusion Mixing Salt finger Southwestern Atlantic Salinity measurement Seawater Thermal diffusion Baroclinicity Oceanography double diffusion fingering salinity vertical mixing water mass Atlantic Ocean Bianchi, A.A. Piola, A.R. Collino, G.J. Evidence of double diffusion in the Brazil-Malvinas Confluence |
| topic_facet |
Brazil/Malvinas Confluence Double diffusion Mixing Salt finger Southwestern Atlantic Salinity measurement Seawater Thermal diffusion Baroclinicity Oceanography double diffusion fingering salinity vertical mixing water mass Atlantic Ocean |
| description |
Observation of thermohaline staircases and low-density ratios in the Brazil-Malvinas Confluence (BMC) suggests salt-fingering activity between the high salinity South Atlantic Central Water and low salinity Antarctic Intermediate Water. Vertical salt-finger induced salt fluxes are estimated in the BMC using a model for fastest growing fingers. Maximum salt-finger fluxes of 39.9 × 10-10 W kg-1 (5.3 × 10-7 m s-1) were estimated, similar to existing estimates in a Mediterranean salt lens embedded within the North Atlantic water. The fluxes normalized by the large-scale property gradients lead to fairly large estimates of diapycnal haline and thermal diffusivities, of up to 0.74 × 10-4 and 0.34 × 10-4 m2s-1, respectively, showing the enhancement of the haline diffusivity due to salt fingers. Estimated diffusive-convection fluxes based on flux laws derived from laboratory experiments are two orders of magnitude larger than salt-finger fluxes. These results suggest that, where cross-front interleaving leads to layering of relatively cold-fresh water over warm-salty water, diffusive upward convection dominates the vertical property fluxes in the frontal region. It appears that on the warm-salty side of the BMC, away from the narrow band dominated by interleaving, salt-finger integrated vertical fluxes nearly balance the cross-front lateral integrated fluxes. The effect of baroclinicity on the vertical property fluxes was evaluated and it was found that, in the BMC, the baroclinicity enhances the interleaving. © 2001 Elsevier Science Ltd. All rights reserved. |
| format |
JOUR |
| author |
Bianchi, A.A. Piola, A.R. Collino, G.J. |
| author_facet |
Bianchi, A.A. Piola, A.R. Collino, G.J. |
| author_sort |
Bianchi, A.A. |
| title |
Evidence of double diffusion in the Brazil-Malvinas Confluence |
| title_short |
Evidence of double diffusion in the Brazil-Malvinas Confluence |
| title_full |
Evidence of double diffusion in the Brazil-Malvinas Confluence |
| title_fullStr |
Evidence of double diffusion in the Brazil-Malvinas Confluence |
| title_full_unstemmed |
Evidence of double diffusion in the Brazil-Malvinas Confluence |
| title_sort |
evidence of double diffusion in the brazil-malvinas confluence |
| url |
http://hdl.handle.net/20.500.12110/paper_09670637_v49_n1_p41_Bianchi |
| work_keys_str_mv |
AT bianchiaa evidenceofdoublediffusioninthebrazilmalvinasconfluence AT piolaar evidenceofdoublediffusioninthebrazilmalvinasconfluence AT collinogj evidenceofdoublediffusioninthebrazilmalvinasconfluence |
| _version_ |
1807324017710858240 |