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Shelf-slope exchanges and particle dispersion in Blanes submarine canyon (NW Mediterranean Sea): A numerical study

Shelf-slope exchanges and particle dispersion in Blanes submarine canyon (NW Mediterranean Sea): A numerical study
Shelf-slope exchanges and particle dispersion in Blanes submarine canyon (NW Mediterranean Sea): A numerical study
A climatological simulation performed with a fine-resolution (?1.2 km) 3D circulation model nested in one-way to a coarse-resolution (?4 km) 3D regional model is used to examine the cross-shelf break water exchange in the Blanes submarine canyon (?41°00?–41°46?N; ?02°24?–03°24?E). A Lagrangian particle-tracking model coupled to the fine-resolution 3D circulation model is used to investigate the role of the incident regional flow (i.e. the Northern Current, NC) and its seasonal variability on the dispersion and residence time of passive particles inside Blanes Canyon. The NC flows southwestward, along the slope, with the coastline to the right. Water is advected offshore/onshore at the upstream/downstream canyon walls, with a net water transport toward the slope (i.e. offshore). The amount of water moved across the shelf break of the upstream wall is approximately three times larger than the amount moved across the shelf break of the downstream wall. This preferential zone for cross-shelf break water exchange is explained by the asymmetric geometry of the canyon and the orientation of the incident current with respect to the canyon bathymetry. Passive particles released upstream Blanes Canyon between the mid-shelf and the upper-slope drift within the NC and accumulate over the shelf edge of the canyon. About half of the particles released at depths above the shelf break move towards shallower areas inside the canyon. In contrast, about two-thirds of particles released below the shelf break move to deeper areas. Particle dispersion is higher under weakly (e.g. winter) than strongly (e.g. summer) stratified conditions. The residence time of passive particles inside the canyon (?4–6 days) is double than the residence time downstream of the canyon, indicating that the canyon acts as an efficient retention zone for passive particles.
Submarine canyon, Shelf-slope exchanges, Particle dispersion, Residence time, Numerical modeling
0278-4343
35 - 45
Ahumada-Sempoal, M.-A.
fffe504f-a17c-4d2e-87fb-4a7c7a1400ff
Flexas, M.M.
6dd23f03-2f6a-489e-9155-508e9c2569ef
Bernardello, R.
7db9abe7-7079-4f14-8397-6371d96e2420
Bahamon, N.
86c2a8d7-5427-4007-95ad-d0efaf606918
Cruzado, A.
c1e91329-d53b-4302-861f-53b247f6ea1f
Reyes-Hernández, C.
39cdcc50-f2a9-4ab7-9ea5-8ba390c6c96f
Ahumada-Sempoal, M.-A.
fffe504f-a17c-4d2e-87fb-4a7c7a1400ff
Flexas, M.M.
6dd23f03-2f6a-489e-9155-508e9c2569ef
Bernardello, R.
7db9abe7-7079-4f14-8397-6371d96e2420
Bahamon, N.
86c2a8d7-5427-4007-95ad-d0efaf606918
Cruzado, A.
c1e91329-d53b-4302-861f-53b247f6ea1f
Reyes-Hernández, C.
39cdcc50-f2a9-4ab7-9ea5-8ba390c6c96f

Ahumada-Sempoal, M.-A., Flexas, M.M., Bernardello, R., Bahamon, N., Cruzado, A. and Reyes-Hernández, C. (2015) Shelf-slope exchanges and particle dispersion in Blanes submarine canyon (NW Mediterranean Sea): A numerical study. Continental Shelf Research, 109, 35 - 45.

Record type: Article

Abstract

A climatological simulation performed with a fine-resolution (?1.2 km) 3D circulation model nested in one-way to a coarse-resolution (?4 km) 3D regional model is used to examine the cross-shelf break water exchange in the Blanes submarine canyon (?41°00?–41°46?N; ?02°24?–03°24?E). A Lagrangian particle-tracking model coupled to the fine-resolution 3D circulation model is used to investigate the role of the incident regional flow (i.e. the Northern Current, NC) and its seasonal variability on the dispersion and residence time of passive particles inside Blanes Canyon. The NC flows southwestward, along the slope, with the coastline to the right. Water is advected offshore/onshore at the upstream/downstream canyon walls, with a net water transport toward the slope (i.e. offshore). The amount of water moved across the shelf break of the upstream wall is approximately three times larger than the amount moved across the shelf break of the downstream wall. This preferential zone for cross-shelf break water exchange is explained by the asymmetric geometry of the canyon and the orientation of the incident current with respect to the canyon bathymetry. Passive particles released upstream Blanes Canyon between the mid-shelf and the upper-slope drift within the NC and accumulate over the shelf edge of the canyon. About half of the particles released at depths above the shelf break move towards shallower areas inside the canyon. In contrast, about two-thirds of particles released below the shelf break move to deeper areas. Particle dispersion is higher under weakly (e.g. winter) than strongly (e.g. summer) stratified conditions. The residence time of passive particles inside the canyon (?4–6 days) is double than the residence time downstream of the canyon, indicating that the canyon acts as an efficient retention zone for passive particles.

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More information

Published date: 15 October 2015
Keywords: Submarine canyon, Shelf-slope exchanges, Particle dispersion, Residence time, Numerical modeling
Organisations: Marine Biogeochemistry

Identifiers

Local EPrints ID: 382300
URI: https://eprints.soton.ac.uk/id/eprint/382300
ISSN: 0278-4343
PURE UUID: d25c805b-0775-43c9-8a00-c164ba4cdba0

Catalogue record

Date deposited: 02 Oct 2015 13:28
Last modified: 05 Oct 2017 00:36

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