Atlantic Water Properties, Transport and Heat Loss From Mooring Observations North of Svalbard

Koenig, Zoé; Kalhagen, Kjersti; Kolås, Eivind; Fer, Ilker; Nilsen, Frank; Cottier, Finlo

doi:10.1029/2022jc018568

Cited by 4 publications

(3 citation statements)

References 47 publications

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“…The observed velocities are dominated by the boundary current, transporting AW into the Arctic Ocean. The boundary current variability has been discussed before 29 and exhibits a substantial seasonal cycle with peak velocities in winter and minima in summer (Fig. 2 ).…”

Section: Methodsmentioning

confidence: 89%

Trapped tidal currents generate freely propagating internal waves at the Arctic continental slope

Baumann,

Fer

2023

Sci Rep

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Energetic tidal currents in the Arctic play an important role in local mixing processes, but they are primarily confined to the shelves and continental slopes due to topographic trapping north of their critical latitude. Recent studies employing idealized models have suggested that the emergence of higher harmonic tidal waves along these slopes could serve as a conduit for tidal energy transmission into the Arctic Basin. Here we provide observational support from an analysis of yearlong observations from three densely-instrumented oceanographic moorings spanning 30 km across the continental slope north of Svalbard ($$\sim$$ ∼ 81.3$$^{\circ }$$ ∘ N). Full-depth current records show strong barotropic diurnal tidal currents, dominated by the K$$_1$$ 1 constituent. These sub-inertial currents vary sub-seasonally and are strongest at the 700-m isobath due to the topographic trapping. Coinciding with the diurnal tide peak in summer 2019, we observe strong baroclinic semidiurnal currents exceeding 10 cm s$$^{-1}$$ - 1 between 500 m and 1000 m depth about 10 km further offshore at the outer mooring. In this semidiurnal band, we identify super-inertial K$$_2$$ 2 waves, and present evidence that their frequency, timing, polarization, propagation direction and depths are consistent with the generation as higher harmonics of the topographically trapped K$$_1$$ 1 tide at the continental slope.

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Section: Methodsmentioning

confidence: 89%

Trapped tidal currents generate freely propagating internal waves at the Arctic continental slope

Baumann,

Fer

2023

Sci Rep

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“…We estimated the uncertainty in the volume transport by constructing a 2D-matrix of error distribution of velocity that takes into account the instrumental error as well as the distance to the closest observation data point so that this uncertainty varies with depth and distance to the data point. This uncertainty section is constructed following the method of Koenig et al, 2022: (a) a nominal uncertainty estimate of the velocity measurements of 0.01 cm•s −1 at each mooring location, (b) one standard deviation of the observed velocity measurements at 4 km distance on both sides of the mooring and (c) two standard deviations of the observed velocity measurements mid-way between pairs of mooring. We choose the conservative value of 4 km as decorrelation scale as it corresponds to the Rossby deformation radius that is about 4-6 km in the region (Nurser & Bacon, 2014).…”

Section: Discussionmentioning

confidence: 99%

Structure and Variability of the Jan Mayen Current in the Greenland Sea Gyre From a Yearlong Mooring Array

Pellichero,

Lique,

Kolodziejczyk

et al. 2023

JGR Oceans

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The Jan Mayen Channel is located North of the Jan Mayen Island in the Nordic Seas, and is an important gateway for the exchanges of volume, heat and freshwater between the Greenland and the Norwegian basins via the Jan Mayen Current. Based on observations from moored instruments deployed on the shelf and the continental slope of the Jan Mayen Island from August 2017 to August 2018, we document the mean state and the variability of the currents, temperature and salinity and their associated vertical structure. We found that the main feature of circulation is an intense and permanent south‐eastward jet‐like current centered at 150 m depth, located on the 400 m depth slope, with a maximum mean magnitude of 7 cm·s−1. While the velocities recorded on the shelf are largely constant in speed and direction, without any strong seasonal cycle, the moorings located offshore are capturing larger anomalies on short time scales that are likely the signature of eddies passing across the mooring array. Overall, the variability of the transport across the section is correlated with the large‐scale wind pattern over the Nordic Seas, highlighting that the Jan Mayen Current is part of a complex system of currents that operates at larger scale in the region.

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“…At the NSv site, a low‐intensity but sustained wind stress event resulted in a well‐mixed water column from January until May (Henley et al., 2020), while a prolonged period of high TPM fluxes was observed from February until April. Although current velocity data are unavailable for the 2017–2018 deployment period, increased current speeds of the AW advected into the area north of Svalbard were recorded during winter 2018–2019 (Koenig et al., 2022). A considerable and sustained disturbance of the seabed favoring resuspension is possible under sustained wind speeds promoting turbulence.…”

Section: Discussionmentioning

confidence: 99%

The Influence of Sea Ice Cover and Atlantic Water Advection on Annual Particle Export North of Svalbard

et al. 2022

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Across the Arctic Ocean, rapid sea ice retreat and thinning are occurring as a consequence of climate change (Stroeve & Notz, 2018). The Eurasian sector of the Arctic Ocean used to have prominent seasonal ice cover but has experienced large sea ice losses in recent years, especially during winter (Onarheim et al., 2018;Polyakov et al., 2017). The area north of Svalbard is part of the European Arctic Corridor with the greatest exchange of water in and out of the Arctic (Wassmann et al., 2010). The largest winter sea ice loss of the entire Arctic Ocean was recorded here between 1979 and 2012 (Onarheim et al., 2014), likely because of increased storm frequency and warmer temperatures of the Atlantic water (AW) advected into the area (Duarte et al., 2020;Renner et al., 2018). Unlike many regions of the Arctic Ocean that are strongly stratified, weakly stratified AW enters the area north and east of Svalbard and is exposed to direct ventilation in winter, caused by cooling and weakening of the halocline during sea-ice formation; a process called Atlantification (Polyakov et al., 2017). The shallower AW inflow

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Atlantic Water Properties, Transport and Heat Loss From Mooring Observations North of Svalbard

Cited by 4 publications

References 47 publications

Trapped tidal currents generate freely propagating internal waves at the Arctic continental slope

Trapped tidal currents generate freely propagating internal waves at the Arctic continental slope

Structure and Variability of the Jan Mayen Current in the Greenland Sea Gyre From a Yearlong Mooring Array

The Influence of Sea Ice Cover and Atlantic Water Advection on Annual Particle Export North of Svalbard

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