On the seasonal variability of the <scp>C</scp>anary <scp>C</scp>urrent and the <scp>A</scp>tlantic <scp>M</scp>eridional <scp>O</scp>verturning <scp>C</scp>irculation

Vélez‐Belchí, P.; Pérez‐Hernández, M. Dolores; Casanova-Masjoan, M.; Cana, L.; Hernández‐Guerra, Alonso

doi:10.1002/2017jc012774

Cited by 23 publications

(45 citation statements)

References 48 publications

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“…The amplitude of the seasonal cycle for fall 2016–spring 2017 equal 4.2 ± 0.34 Sv, comparable to an amplitude of 3.7 ± 0.4 Sv estimated by Vélez‐Belchí et al (2017) for the Eastern Boundary (EB). Unlike for 2016–2017, the amplitude for fall 2017‐spring 2018 is higher, equaling 7.6 ± 0.6 Sv, a value comparable in magnitude to that estimated by Pérez‐Herández et al (2015) for the Atlantic basin at 26°N.…”

Section: Final Geostrophic Transportsupporting

confidence: 85%

Variability of the Canary Current Diagnosed by Inverse Box Models

et al. 2020

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Four hydrographic cruises carried out between ~26.5 and 31°N in the eastern North Atlantic Subtropical Gyre in fall (2016 and 2017) and spring (2017 and 2018) are used to identify water masses and infer oceanic circulation. Geostrophic velocities are initially adjusted by referencing them to data from a Lower Acoustic Doppler Current Profiler (LADCP) and later to velocities estimated with an inverse box model. The distribution of the intermediate water masses (700 to 1,400 m depth) varies seasonally. Antarctic Intermediate Water (AAIW) comprises the largest contributor to the seasonal cycle in the intermediate water masses. Circulation of the Canary Current (CC) differs in fall and spring. In fall, the CC flows southward through the western islands and recirculates south of the archipelago, subsequently flowing northward through the passage between the eastern islands and Africa. North of Lanzarote, the recirculated CC intensified as it is joined by a southeasterly branch of the CC north of Lanzarote. In spring, the net transport of the CC is southward. High interannual variability in mass transport is evident in both spring and fall as a result of the position of the current, with its easternmost (westernmost) position found in spring (fall) 2018 (2016). At intermediate levels, highly variable northward/southward transport is apparent in fall over the African slope, with the Intermediate Poleward Under Current (IPUC) only present in 2017.

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Section: Final Geostrophic Transportsupporting

confidence: 85%

Variability of the Canary Current Diagnosed by Inverse Box Models

et al. 2020

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“…To analyse the role of tidal current speed on the source mechanism of tremors, we computed the kinetic energy from the current-meter velocity recordings at the Eastern Boundary Current 4 (EBC4) mooring (e.g., Vélez-Belchí et al, 2017). These instruments acquire velocity, temperature, salinity, and pressure data at a sampling time of 2 hours and are located close to the OBS network (Figure 1).…”

Section: Nature Of the Harmonic Tremors And Short Duration Eventsmentioning

confidence: 99%

Seismicity and Noise Recorded by Passive Seismic Monitoring of Drilling Operations Offshore the Eastern Canary Islands

Ugalde

Gaite

Ruiz

et al. 2019

Seismological Research Letters

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In November 2014 a temporary land and marine seismic network was deployed to monitor the drilling of an exploratory well in the Canary Channel (Eastern Canary Islands). This region is characterized by low seismic activity; however, because of the increased awareness of the potential seismic hazard caused by hydrocarbon exploitation activities, the drilling operations were monitored with an unprecedented level of detail for an activity of this kind. According to the reported earthquakes, there was not a measurable increase in seismicity in the vicinity of the well. Overall seismic activity was low, which is consistent with the historical seismicity records. Harmonic tremor, explained here as resonances of the instrument-seafloor system generated by bottom water currents in the area, was commonly detected on the ocean bottom seismometer (OBS) recordings. The marine network data also revealed few dozens of non-seismic short-duration signals per day that appear similar to other events on OBS recorded throughout the world. We suggest that they may be caused by direct perturbations on the OBS, mostly induced by ocean currents in the Canary Channel.

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“…Further north at Cape Ghir at 30 • N, it is weaker in the annual mean, but with a late spring to August summer maximum (Mittelstaedt, 1991). The component parallel to the coast with its maximum in spring and summer creates the strongest coastal upwelling, with maxima depending regionally on the wind maxima in summer (Van Camp et al, 1991). The offshore Ekman transport is confined to the near surface and has two further effects.…”

Section: Introductionmentioning

confidence: 99%

Long-Term Changes of Particle Flux in the Canary Basin Between 1991 and 2009 and Comparison to Sediment Trap Records Off Mauritania

et al. 2020

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Eastern Boundary Upwelling Ecosystems (EBUEs) are associated with high biological productivity, high fish catch and they highly contribute to marine carbon sequestration. Whether coastal upwelling has intensified or weakened under climate change in the past decades is controversially discussed and different approaches (e.g., timeseries of chlorophyll, wind, sea surface temperature, modeling experiments) have been considered. We present a record of almost two decades of particle fluxes (1991-2009) from ca. 600 to 3100 m water depth in the Canary Basin at site ESTOC (European Station for Time series in the Ocean Canary Islands; ca. 29 • N, 15 • 30.W, ca. 3600 m water depth), located in the offshore transition zone of the northern Canary Current-EBUE. We compare these flux records with those measured at a mesotrophic sediment trap site further south off Cape Blanc (Mauritania, ca. 21 • N). The deep ocean fluxes at ESTOC in ca. 3 km recorded the evolution of the coastal Cape Ghir filament (30-32 • N, 10-12 • W) due to lateral advection of particles, whereas the upper water column sediment traps in ca. 1 km reflected the oligotrophic conditions in the overlying waters of ESTOC. We observed an increased emphasis in springtime fluxes since 2005, associated with a change in particle composition, while satellite chlorophyll biomass did not show this pattern. Due to its northern location in the CC-EBUEs, spring biogenic fluxes at ESTOC provide a better relationship to the forcing of the North Atlantic Oscillation than those recorded further south off Cape Blanc. Off Cape Blanc, deep fluxes showed the best overlap with the deep ESTOC fluxes during the spring season before 2005. On the long-term, both chlorophyll and particle fluxes showed an increasing trend at ESTOC which was not observed further south at the mesotrophic Cape Blanc site. This might indicate that, depending on their location along the NW African margin, coastal upwelling systems react differently to global change.

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On the seasonal variability of the Canary Current and the Atlantic Meridional Overturning Circulation

Cited by 23 publications

References 48 publications

Variability of the Canary Current Diagnosed by Inverse Box Models

Variability of the Canary Current Diagnosed by Inverse Box Models

Seismicity and Noise Recorded by Passive Seismic Monitoring of Drilling Operations Offshore the Eastern Canary Islands

Long-Term Changes of Particle Flux in the Canary Basin Between 1991 and 2009 and Comparison to Sediment Trap Records Off Mauritania

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