Seasonal Variability in Warm-Water Inflow toward Kangerdlugssuaq Fjord

Gelderloos, Renske; Haine, Thomas W. N.; Koszalka, Inga Monika; Magaldi, Marcello G.

doi:10.1175/jpo-d-16-0202.1

Cited by 17 publications

(19 citation statements)

References 50 publications

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“…The IC/EGC front is prone to meandering and eddy shedding (Magaldi et al, ), giving rise to variability in the water mass structure on shelf and, crucially, allowing AW to flow westward of the shelf break, such that water mass exchange between the Irminger Basin and the shelf is episodic in nature. In a SE Greenland regional model by Gelderloos et al (), a branch of the IC is seen to circulate into KT at the shelf break while, in summer, a second branch is found to go north through the Denmark Strait and across the shelf toward KT, thus advecting AW toward the mouth of the KF. The densest water mass in the region is Denmark Strait Overflow Water (DSOW,

Θ < 0

°C,

34.9 < S_{A} < 35.2

σ_{θ} \geq 27.8

).…”

Section: Introductionmentioning

confidence: 99%

Influence of Barrier Wind Forcing on Heat Delivery Toward the Greenland Ice Sheet

Fraser

Inall

2018

JGR Oceans

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A high‐resolution numerical hydrodynamic model of Kangerdlugssuaq Fjord and the adjacent southeast Greenland shelf region was constructed in order to investigate the dynamics of fjord‐shelf exchange. Recent studies have suggested that rapid exchange flows, driven by along‐shelf barrier wind events, are the dominant agent of exchange between fjord and shelf. These events are prone to occur during the winter, when freshwater forcing is minimal and observations of the fjord interior are scarce. Subglacial freshwater discharge was held at zero, so that any buoyancy‐driven overturning circulation was driven by melting alone. The model described a geostrophically balanced background flow transporting water masses between the fjord mouth and the glacier terminus, indicating that rotational effects are of order‐one importance. Barrier wind events were found to trigger coastally trapped internal wave activity within fjord, temporarily enhancing exchange and vertical mixing, and causing warm water to oscillate in the along‐fjord direction. These internal waves were also found to enhance the background flow via Stokes' drift. Heat delivery through the fjord mouth was smaller than that recorded in summer observations, however the system is more effective at delivering this heat to the head of the fjord. There exists the potential for wintertime melting at the ice‐ocean interface to be significant to the same order as summertime melting.

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Θ < 0

°C,

34.9 < S_{A} < 35.2

σ_{θ} \geq 27.8

).…”

Section: Introductionmentioning

confidence: 99%

Influence of Barrier Wind Forcing on Heat Delivery Toward the Greenland Ice Sheet

Fraser

Inall

2018

JGR Oceans

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“…Across this line (fig. S1), a clear inflow along the eastern boundary and outflow on the western boundary confirm the presumed geostrophic circulation ( 19 , 22 , 23 ). However, in contrast to expectations, the isohalines are deepest in the outflow on the western side of the trough, yielding a slight export of 0.04 Sv of waters fresher than 34 from the trough.…”

Section: Resultsmentioning

confidence: 59%

“…Surface runoff and solid ice discharge from Greenland are incorporated into the model forcings by adding water volume at the surface distributed over grid points near the glaciers as well as time-varying full-water column restoring of temperature and salinity at these grid points to account for plume entrainment. This model has been shown to accurately simulate the circulation in the Denmark Strait region ( 22 , 37 , 38 ). Model-based quantities have been extracted and calculated using OceanSpy ( 39 ).…”

Section: Methodsmentioning

confidence: 99%

A continuous pathway for fresh water along the East Greenland shelf

2020

Self Cite

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Export from the Arctic and meltwater from the Greenland Ice Sheet together form a southward-flowing coastal current along the East Greenland shelf. This current transports enough fresh water to substantially alter the large-scale circulation of the North Atlantic, yet the coastal current’s origin and fate are poorly known due to our lack of knowledge concerning its north-south connectivity. Here, we demonstrate how the current negotiates the complex topography of Denmark Strait using in situ data and output from an ocean circulation model. We determine that the coastal current north of the strait supplies half of the transport to the coastal current south of the strait, while the other half is sourced from offshore via the shelfbreak jet, with little input from the Greenland Ice Sheet. These results indicate that there is a continuous pathway for Arctic-sourced fresh water along the entire East Greenland shelf from Fram Strait to Cape Farewell.

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“…The velocity field of an OGCM is used to calculate a large set of individual particle trajectories, with each particle describing the pathway of an imaginary point particle, that moves as a small element of fluid. Example applications of such Lagrangian studies target the spread of geochemical tracers (e.g., Gary et al 2012), simulation of tracer release experiments (Banyte et al 2013), spreading of water masses (e.g., Bower et al 2009;Koszalka et al 2013;Rühs et al 2013;Durgadoo et al 2017), back-tracing sources of water masses (von Appen et al 2014;Gelderloos et al 2017), or calculation of eddy diffusivities in eddy-permitting or eddy-resolving models (Koszalka et al 2009a;Griesel et al 2010Griesel et al , 2014Rühs et al 2018).…”

Section: Introductionmentioning

confidence: 99%

“…Lagrangian experiments also offer the ability to perform backward tracing and the capacity to calculate conditional statistics, like transit time distributions and water property changes, on subsets of the trajectories. (e.g., von Appen et al 2014;Durgadoo et al 2017;Gelderloos et al 2017). Acoustically tracked Lagrangian floats (following the currents at a certain pressure or density surface) have also been used to assess lateral water mass pathways and eddy diffusivities in the subpolar North Atlantic and in the Southern Ocean (e.g., Zhang et al 2001;Bower et al 2009).…”

Section: Introductionmentioning

confidence: 99%

Can Lagrangian Tracking Simulate Tracer Spreading in a High-Resolution Ocean General Circulation Model?

Wagner

Rühs

Schwarzkopf

et al. 2019

Journal of Physical Oceanography

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To model tracer spreading in the ocean, Lagrangian simulations in an offline framework are a practical and efficient alternative to solving the advective–diffusive tracer equations online. Differences in both approaches raise the question of whether both methods are comparable. Lagrangian simulations usually use model output averaged in time, and trajectories are not subject to parameterized subgrid diffusion, which is included in the advection–diffusion equations of ocean models. Previous studies focused on diffusivity estimates in idealized models but could show that both methods yield similar results as long as the deformations-scale dynamics are resolved and a sufficient amount of Lagrangian particles is used. This study compares spreading of an Eulerian tracer simulated online and a cloud of Lagrangian particles simulated offline with velocities from the same ocean model. We use a global, eddy-resolving ocean model featuring 1/20° horizontal resolution in the Agulhas region around South Africa. Tracer and particles were released at one time step in the Cape Basin and below the mixed layer and integrated for 3 years. Large-scale diagnostics, like mean pathways of floats and tracer, are almost identical and 1D horizontal distributions show no significant differences. Differences in vertical distributions, seen in a reduced vertical spreading and downward displacement of particles, are due to the combined effect of unresolved subdaily variability of the vertical velocities and the spatial variation of vertical diffusivity. This, in turn, has a small impact on the horizontal spreading behavior. The estimates of eddy diffusivity from particles and tracer yield comparable results of about 4000 m2 s−1 in the Cape Basin.

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Seasonal Variability in Warm-Water Inflow toward Kangerdlugssuaq Fjord

Cited by 17 publications

References 50 publications

Influence of Barrier Wind Forcing on Heat Delivery Toward the Greenland Ice Sheet

Influence of Barrier Wind Forcing on Heat Delivery Toward the Greenland Ice Sheet

A continuous pathway for fresh water along the East Greenland shelf

Can Lagrangian Tracking Simulate Tracer Spreading in a High-Resolution Ocean General Circulation Model?

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