Article (Scientific journals)
Generation of the Cape Ghir upwelling filament: A numerical study
Troupin, Charles; Mason, Evan; Beckers, Jean-Marie et al.
2012In Ocean Modelling, 41, p. 1-15
Peer Reviewed verified by ORBi
 

Files


Full Text
Troupin2011Filament0M_revised3.pdf
Author preprint (5.96 MB)
Download

All documents in ORBi are protected by a user license.

Send to



Details



Keywords :
Eastern boundary; Canary Upwelling system; Upwelling filaments; Potential vorticity; ROMS model
Abstract :
[en] Filaments are narrow, shallow structures of cool water originating from the coast. They are typical features of the four main eastern boundary upwelling systems (EBUS). In spite of their significant biological and chemical roles, through the offshore exportation of nutrient-rich waters, the physical processes that generate them are still not completely understood. This paper is a process-oriented study of filament generation mechanisms. Our goal is twofold: firstly, to obtain a numerical solution able to well represent the characteristics of the filament off Cape Ghir (30°38'N, northwestern Africa) in the Canary EBUS and secondly, to explain its formation by a simple mechanism based on the balance of potential vorticity. The first goal is achieved by the use of the ROMS model (Regional Ocean Modeling System) in embedded domains around Cape Ghir, with a horizontal resolution going up to 1.5 km for the finest domain. The latter gets its initial and boundary conditions from a parent solution and is forced by climatological, high-resolution atmospheric fields. The modeled filaments display spatial, temporal and physical characteristics in agreement with the available in situ and satellite observations. This model solution is used as a reference to compare the results with a set of process-oriented experiments. These experiments allow us to reach the second objective. Their respective solution serves to highlight the contribution of various processes in the filament generation. Since the study is focused on general processes present under climatological forcing conditions, inter-annual forcing is not necessary. The underlying idea for the filament generation is the balance of potential vorticity in the Canary EBUS: the upwelling jet is characterized by negative relative vorticity and flows southward along a narrow band of uniform potential vorticity. In the vicinity of the cape, an injection of relative vorticity induced by the wind breaks the existing vorticity balance. The upwelling jet is prevented from continuing its way southward and has to turn offshore to follow lines of equal potential vorticity. The model results highlight the essential role of wind, associated with the particular topography (coastline and bottom) around the cape. The mechanism presented here is general and thus can be applied to other EBUS.
Disciplines :
Earth sciences & physical geography
Author, co-author :
Troupin, Charles  ;  Université de Liège - ULiège > Département d'astrophys., géophysique et océanographie (AGO) > GeoHydrodynamics and Environment Research (GHER)
Mason, Evan;  Mediterranean Institute for Advanced Studies > Marine Technologies, Operational Oceanography and Sustainability
Beckers, Jean-Marie  ;  Université de Liège - ULiège > Département d'astrophys., géophysique et océanographie (AGO) > GeoHydrodynamics and Environment Research (GHER)
Sangrà, Pablo;  Universidad de Las Palmas de Gran Canaria (Spain) > Ciencias del Mar > Física
Language :
English
Title :
Generation of the Cape Ghir upwelling filament: A numerical study
Alternative titles :
[en] Generation du filament d'upwelling de Cap Ghir: une étude numérique
Publication date :
2012
Journal title :
Ocean Modelling
ISSN :
1463-5003
eISSN :
1463-5011
Publisher :
Elsevier Science, Oxford, United Kingdom
Volume :
41
Pages :
1-15
Peer reviewed :
Peer Reviewed verified by ORBi
Available on ORBi :
since 13 October 2011

Statistics


Number of views
168 (11 by ULiège)
Number of downloads
337 (2 by ULiège)

Scopus citations®
 
19
Scopus citations®
without self-citations
15
OpenCitations
 
18

Bibliography


Similar publications



Contact ORBi