Structure and transport of the Iceland Scotland Overflow plume along the Reykjanes Ridge in the Iceland Basin

Kanzow, Torsten; Zenk, Walter

doi:10.1016/j.dsr.2013.11.003

Cited by 44 publications

(69 citation statements)

References 43 publications

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“…Indeed this has been observed with moored current meters along the EEL in the Rockall Trough [Holliday et al, 2000]. However, in the eastern Iceland Basin the upper waters, LSW and ISOW are all moving in a general north-eastward direction; the recirculation of ISOW in this area being confirmed by current meter measurements [Kanzow and Zenk, 2014]. Therefore in the eastern Iceland Basin, and shallow Hatton-Rockall Basin, no flow reversal is expected mid water column and we consider the LoNM to be at the seabed.…”

Section: 1002/2015jc010762mentioning

confidence: 53%

Multidecadal variability of potential temperature, salinity, and transport in the eastern subpolar North Atlantic

et al. 2015

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The Extended Ellett Line (EEL) hydrographic section extends from Scotland to Iceland crossing the Rockall Trough, Hatton‐Rockall Basin, and Iceland Basin. With 61 full‐depth stations at a horizontal resolution of 10–50 km, the EEL samples the upper limb of the Atlantic Meridional Overturning Circulation flowing across the Iceland‐Scotland Ridge into the Nordic Seas. The Rockall Trough has been sampled nearly four times per year from 1975 to 1996, and the full section annually since 1996. The EEL is an exceptionally long‐time series of deep ocean temperatures and salinities. This study extends prior work in the Rockall Trough, and examines for the first time 18 year records in the Iceland and Hatton‐Rockall Basins. We quantify errors in the time series from two sources: observational errors and aliasing. The data quality and annual sampling are suitable for observing interannual to decadal variability because the variability exceeds our error estimates. The upper waters of all three basins are cooler/fresher from 1997 to 2001, warmer/more saline 2001–2006, and cooler/fresher from 2006 to 2014. A reference level for geostrophic shear is developed heuristically and by comparison with sea‐surface altimetry. The mean northward transport in the upper waters is 6.7 ± 3.7 Sv and there is a 6.1 ± 2.5 Sv southward flow below the thermocline. Although the magnitude of the Iceland Basin overturning circulation (4.3 ± 1.9 Sv) is greater than in the Rockall Trough (3.0 ± 3.7 Sv), the variability is greater in the Rockall Trough. We discuss the results in the context of our understanding of drivers of variability.

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Section: 1002/2015jc010762mentioning

confidence: 53%

Multidecadal variability of potential temperature, salinity, and transport in the eastern subpolar North Atlantic

et al. 2015

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“…Particularly relevant to the topic here, Xu et al (2010) considered the volume transport and u/S properties of overflow waters after they flow over the GreenlandScotland Ridge into and within the Irminger Sea. The multiple ISOW pathways in the model [see Kanzow and Zenk (2014) for observational support] provide a possible explanation for the small westward transport observed in ISOW through the Charlie-Gibbs Fracture Zone (CGFZ), which is roughly 60% of deep transport upstream and downstream. Comparison with available long-term moored instrument databases shows reasonable agreement with the observed transports of overflow water with approximately correct u/S characteristics.…”

Section: Model Configurationsmentioning

confidence: 99%

Spreading of Denmark Strait Overflow Water in the Western Subpolar North Atlantic: Insights from Eddy-Resolving Simulations with a Passive Tracer

Rhines

Chassignet

et al. 2015

Journal of Physical Oceanography

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The oceanic deep circulation is shared between concentrated deep western boundary currents (DWBCs) and broader interior pathways, a process that is sensitive to seafloor topography. This study investigates the spreading and deepening of Denmark Strait overflow water (DSOW) in the western subpolar North Atlantic using two 1 /128 eddy-resolving Atlantic simulations, including a passive tracer injected into the DSOW. The deepest layers of DSOW transit from a narrow DWBC in the southern Irminger Sea into widespread westward flow across the central Labrador Sea, which remerges along the Labrador coast. This abyssal circulation, in contrast to the upper levels of overflow water that remain as a boundary current, blankets the deep Labrador Sea with DSOW. Farther downstream after being steered around the abrupt topography of Orphan Knoll, DSOW again leaves the boundary, forming cyclonic recirculation cells in the deep Newfoundland basin. The deep recirculation, mostly driven by the meandering pathway of the upper North Atlantic Current, leads to accumulation of tracer offshore of Orphan Knoll, precisely where a local maximum of chlorofluorocarbon (CFC) inventory is observed. At Flemish Cap, eddy fluxes carry ;20% of the tracer transport from the boundary current into the interior. Potential vorticity is conserved as the flow of DSOW broadens at the transition from steep to less steep continental rise into the Labrador Sea, while around the abrupt topography of Orphan Knoll, potential vorticity is not conserved and the DSOW deepens significantly.

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“…To conclude, even though the ISOW is the main current along the northern MAR up to the CGFZ, its influence on deep-sea sponge dispersal and distribution is poorly understood. One of the main reasons may be that the ISOW itself is still not fully understood (Kanzow & Zenk, 2014).…”

Section: Northern Mid-atlantic Demospongesmentioning

confidence: 99%

Demosponges from the Northern Mid-Atlantic Ridge shed more light on the diversity and biogeography of North Atlantic deep-sea sponges

Cárdenas

Rapp

2015

J. Mar. Biol. Ass.

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In July-August 2004, the Mid-Atlantic Ridge Ecosystems (MAR-Eco) expedition collected Demospongiae (Porifera) from the Northern Mid-Atlantic Ridge (MAR) north of the Azores, between 418N and 618N. Demosponges were found at 10 stations, at depths ranging from 753 to 3046 m. Twenty-two species were identified: 17 Tetractinellida, one Polymastiida, one Suberitida, two Poecilosclerida and one Dendroceratida. The study of this material is an opportunity to revise the taxonomy and the North Atlantic distribution of each of these deep-sea species. Some species are particularly rare and poorly known (Tetilla longipilis, Tetilla sandalina, Craniella azorica, Polymastia corticata) and two are new to science: Forcepia (Forcepia) toxafera sp. nov. and Iotroata paravaridens sp. nov. This study suggests that the MAR is not a longitudinal barrier for the dispersal of deep-sea demosponges while on the contrary, the Charlie-Gibbs Fracture Zone (CGFZ) may be a latitudinal border for the dispersal of deep-sea demosponges, due to great depths and currents.

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Structure and transport of the Iceland Scotland Overflow plume along the Reykjanes Ridge in the Iceland Basin

Cited by 44 publications

References 43 publications

Multidecadal variability of potential temperature, salinity, and transport in the eastern subpolar North Atlantic

Multidecadal variability of potential temperature, salinity, and transport in the eastern subpolar North Atlantic

Spreading of Denmark Strait Overflow Water in the Western Subpolar North Atlantic: Insights from Eddy-Resolving Simulations with a Passive Tracer

Demosponges from the Northern Mid-Atlantic Ridge shed more light on the diversity and biogeography of North Atlantic deep-sea sponges

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