Island-induced eddies in the Canary islands

Arı́stegui, Javier; Sangrà, Pablo; Hernández‐León, Santiago; Cantón, Manuel Alías; Hernández‐Guerra, Alonso; Kerling, Jeffrey L.

doi:10.1016/0967-0637(94)90058-2

Cited by 178 publications

(122 citation statements)

References 23 publications

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“…By a classical mechanism of formation of eddies in the lee of an obstacle, the wake can also generate mesoscale eddies, as indicated by the observations reported downstream of Gran Canaria Island (Aristegui et al, 1994(Aristegui et al, , 1997Barton et al, 2000). In the case of Hawaii, south (north) of the HLCC these eddies are typically anticyclonic (cyclonic) (Lumpkin, 1998).…”

Section: Introductionmentioning

confidence: 87%

Sensitivity study of the generation of mesoscale eddies in a numerical model of Hawaii islands

2011

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Abstract. The oceanic circulation around the Hawaiian archipelago is characterized by a complex circulation and the presence of mesoscale eddies west of the islands. These eddies typically develop and persist for weeks to several months in the area during persistent trade winds conditions. A series of numerical simulations on the Hawaiian region has been done in order to examine the relative importance of wind, inflow current and topographic forcing on the general circulation and the generation of eddies. Moreover, numerical cyclonic eddies are compared with the one observed during the cruise E-FLUX . Our study demonstrates the need for all three forcings (wind, inflow current and topography) to reproduce the known oceanic circulation. In particular, the cumulative effect plays a key role on the generation of mesoscale eddies. The wind-stress-curl, via the Ekman pumping mechanism, has also been identified as an important mechanism upon the strength of the upwelling in the lee of the Big Island of Hawaii. In order to find the best setup of a regional ocean model, we compare more precisely numerical results obtained using two different wind databases: COADS and QuikSCAT. The main features of the ocean circulation in the area are well reproduced by our model forced by both COADS and QuickSCAT climatologies. Nevertheless, significant differences appear in the levels of kinetic energy and vorticity. The wind-forcing spatial resolution clearly affects the way in which the wind momentum feeds the mesoscale phenomena. The higher the resolution, the more realistic the ocean circulation. In particular, the simulation forced by QuikSCAT wind data reproduces well the observed energetic mesoscale structures and their hydrological characteristics and behaviors.

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Section: Introductionmentioning

confidence: 87%

Sensitivity study of the generation of mesoscale eddies in a numerical model of Hawaii islands

2011

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“…In fact, the two stations with the greatest concentration of gobid larvae and a smaller percentage of oceanic larvae were two coastal stations sampled during the second leg of this cruise with one located to the north and the other to the south of this island. These two stations, because of particular conditions of water circulation around Gran Canaria (Van Camp et al, 1991;Hernández-Guerra et al, 1993;Arístegui et al, 1994Arístegui et al, , 1997Barton et al, 1998;Martínez et al, 1999;Rodríguez et al, unpublished data) would have been those that presented more neritic characteristics. …”

Section: Discussionmentioning

confidence: 99%

Fish larvae from the Canary region in autumn

Rodrı́guez¹

2000

Sci. Mar.

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SUMMARY: In this paper, the taxonomic composition of the fish larvae community in the Canary region in autumn 1991 is presented. In total, 8699 larvae belonging to 58 fish families were studied. 176 taxonomic groups were identified, 149 at species level and the rest were identified at a higher level. The most numerous family and the one that presented the greatest number of species was Myctophidae. The most frequently caught species was Cyclothone braueri. The taxonomic composition (at family level) of the fish larvae community, dominated by four mesopelagic families, was typical of oceanic regions of warm waters. The most remarkable feature of the fish larvae community was its high specific diversity.

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“…These trajectories are generated all along the coast of the CANUS (Figure 11a), but more particularly between 258N and the Canary Islands. This region presents an enhanced eddy generation due to the unstable currents and winds [Ar ıstegui et al, 1994[Ar ıstegui et al, , 1997Barton et al, 1998;Pacheco and Hernandez-Guerra, 1999;Barton and Ar ıstegui, 2004;Sangr a et al, 2009]. In contrast, 40% of the sampled trajectories are associated with subsurface-intensified eddies showing significant maximum h 0 of 0.68C and S 0 of 0.12 around the pycnocline depth and extending down to 500 m depth (Figures 11f and 11g).…”

Section: Canary Upwelling System (Canus)mentioning

confidence: 99%

“…These CEs and AEs have similarly shaped vertical h 0 and S 0 . Weaker eddies are mainly generated south of the Canary Island, where instabilities lead to the formation of numerous eddies [Ar ıstegui et al, 1994;Sangr a et al, 2007Sangr a et al, , 2009. Nevertheless, the majority of these weak eddies are robust enough to survive more than 30 days and propagate over large distances, thus may play a role on the mixing of tracers despite their nonsignificant anomalies.…”

Section: 1002/2015jc010950mentioning

confidence: 99%

Main eddy vertical structures observed in the four major Eastern Boundary Upwelling Systems

2015

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In the four major Eastern Boundary Upwelling Systems (EBUS), mesoscale eddies are known to modulate the biological productivity and transport near‐coastal seawater properties toward the offshore ocean, however little is known about their main characteristics and vertical structure. This study combines 10 years of satellite‐altimetry data and Argo float profiles of temperature and salinity, and our main goals are (i) to describe the main surface characteristics of long‐lived eddies formed in each EBUS and their evolution, and (ii) to depict the main vertical structure of the eddy‐types that coexist in these regions. A clustering analysis of the Argo profiles surfacing within the long‐lived eddies of each EBUS allows us to determine the proportion of surface and subsurface‐intensified eddies in each region, and to describe their vertical structure in terms of temperature, salinity and dynamic height anomalies. In the Peru‐Chile Upwelling System, 55% of the sampled anticyclonic eddies (AEs) have subsurface‐intensified maximum temperature and salinity anomalies below the seasonal pycnocline, whereas 88% of the cyclonic eddies (CEs) are surface‐intensified. In the California Upwelling System, only 30% of the AEs are subsurface‐intensified and all of the CEs show maximum anomalies above the pycnocline. In the Canary Upwelling System, ∼40% of the AEs and ∼60% of the CEs are subsurface‐intensified with maximum anomalies extending down to 800 m depth. Finally, the Benguela Upwelling System tends to generate ∼40–50% of weak surface‐intensified eddies and ∼50–60% of much stronger subsurface‐intensified eddies with a clear geographical distribution. The mechanisms involved in the observed eddy vertical shapes are discussed.

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Island-induced eddies in the Canary islands

Cited by 178 publications

References 23 publications

Sensitivity study of the generation of mesoscale eddies in a numerical model of Hawaii islands

Sensitivity study of the generation of mesoscale eddies in a numerical model of Hawaii islands

Fish larvae from the Canary region in autumn

Main eddy vertical structures observed in the four major Eastern Boundary Upwelling Systems

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