A process-oriented modelling study of the coastal Canary and Iberian Current system

Batteen, Mary L.; Martinho, Antonio S.; Miller, Henry A.; McClean, Julie L.

doi:10.1016/j.ocemod.2007.02.006

Cited by 16 publications

(7 citation statements)

References 51 publications

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“…While Haidvogel et al [1991] suggested that irregularities in the topography were necessary to trigger the instability, Marchesiello et al [2003] noted that eddies and filaments could develop over a flat bottom and a straight coast line, in agreement with Røed and Shi [1999]. They only noted an anchoring of the filamentary structures near capes, similar to the conclusions of Batteen [1997] and Batteen et al [2007]. Noting that unstable meanders of buoyancy driven coastal currents propagated downstream [ Ikeda and Apel , 1981; Ikeda et al , 1989], Meunier et al [2010] investigated the mechanism responsible for the repeated occurrence and the trapping observed at some particular locations, even in the case of a straight coast line.…”

Section: Introductionmentioning

confidence: 56%

“…Many numerical studies have focused on the dynamics of upwelling filaments, highlighting the variety of physical processes possibly responsible for their formation and evolution. The formation of steep meanders through intrinsic baroclinic instability of the upwelling front was investigated by Ikeda and Apel [1981], Ikeda et al [1989], Haidvogel et al [1991], Batteen [1997], Capet et al [2002], Marchesiello et al [2003], Capet and Carton [2004], Batteen et al [2007], and Meunier et al [2012]. They all agreed in the meander‐like nature of the filaments, but some studies differed on the role of the coast‐line geometry and the bottom topography especially in the trapping of the filaments.…”

Section: Introductionmentioning

confidence: 96%

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Upwelling filaments off Cap Blanc: Interaction of the NW African upwelling current and the Cape Verde frontal zone eddy field?

et al. 2012

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The hydrographical and dynamical properties of the upwelling filaments forming off Cap Blanc (Mauritania) are investigated using remotely sensed and in situ data collected in April/May 2009 during the strongest upwelling season. The area is situated at the southern edge of the NW African upwelling system, where the Cape Verde Frontal Zone (CVFZ) separates warmer, saltier North Atlantic Central Water (NACW) and cooler, fresher South Atlantic Central Water (SACW). Sea surface temperature images indicated the presence of an upwelling filament extending >280 km offshore, rooted over the Cap Blanc promontory and entrained around a warm‐core anticyclonic eddy. After this filament started to decay, a new cold filament developed at the approximate same location. High resolution Moving Vessel Profiler (MVP) and Acoustic Doppler Current Profiler (ADCP) surveys of these mesoscale structures revealed that both filaments were carrying South Atlantic Central Water (SACW) offshore through an intense jet‐like flow. Similarity of the relative vorticity structure across the filament with that of the tangent eddy suggested that the latter was responsible for the offshore current. Tracking of this eddy in altimetric data demonstrated that it originated from the CVFZ, as implied by its hydrographic structure. Altimetric data also revealed that another anticyclonic structure centered over the Cap Blanc promontory was responsible for the northwestward advection of SACW into the base of the filament. The results support the idea that some upwelling filaments can be produced by the interaction of an external eddy field, including topographic eddies, with the upwelled water.

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Section: Introductionmentioning

confidence: 56%

Section: Introductionmentioning

confidence: 96%

Upwelling filaments off Cap Blanc: Interaction of the NW African upwelling current and the Cape Verde frontal zone eddy field?

et al. 2012

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“…For the process-oriented simulations, only one modification with respect to the baseline configuration (Section 2) is done at a time, similarly to the approach of Batteen et al (2007). The numerical experiments combine the different forcing conditions and bathymetries described in the following and summarized in Tab.…”

Section: Process-oriented Numerical Experimentsmentioning

confidence: 99%

“…Their experiments underlined the role played by the wind in the generation of filaments and the importance of the coastline to obtain realistic locations. Another processoriented study was conducted by Batteen et al (2007) in the same area with a terrain-following, 3 km-resolution model. Filament structures were obtained off Cape Ghir when an iterative topography developed by Martinho and Batteen (2006) was used, while the Gaussian smoothed topography only generated little mesoscale activity.…”

Section: Introductionmentioning

confidence: 99%

Generation of the Cape Ghir upwelling filament: A numerical study

et al. 2012

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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 correctly represent the characteristics of the filament off Cape Ghir (30• 38'N, northwest 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) with 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. The solutions serve to highlight the contributions of various processes to 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.

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“…According to Mellor et al (1998), the slope parameter must be less than 0.2 at all locations in order to decrease the pressure gradient force error to an acceptable error (i.e., $0.5 cm s À1 ). This smoothing technique uses an iterative, one-dimensional smoothing method, and has been successfully used in the modeling of the coastal Canary and Iberian current system (Batteen et al, 2007b).…”

Section: Data Setsmentioning

confidence: 99%

Process-oriented modeling studies of the 5500-km-long boundary flow off western and southern Australia

Batteen

Miller

2009

Continental Shelf Research

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A process-oriented modelling study of the coastal Canary and Iberian Current system

Cited by 16 publications

References 51 publications

Upwelling filaments off Cap Blanc: Interaction of the NW African upwelling current and the Cape Verde frontal zone eddy field?

Upwelling filaments off Cap Blanc: Interaction of the NW African upwelling current and the Cape Verde frontal zone eddy field?

Generation of the Cape Ghir upwelling filament: A numerical study

Process-oriented modeling studies of the 5500-km-long boundary flow off western and southern Australia

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