Thermodynamic and Dynamic Ice Thickness Changes in the Canadian Arctic Archipelago in NEMO-LIM2 Numerical Simulations

Hu, Xianmin; Sun, Jingfan; Chan, Ting On; Myers, Paul G.

doi:10.5194/tc-2017-197

Cited by 2 publications

(2 citation statements)

References 21 publications

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“…There is no salinity restoring. Further details, as well as model evaluation, can be found in Hu et al () and Courtois et al (). The passive tracer is introduced into the model at the Bering Strait uniformly with depth, starting from the beginning of the model experiment on 1 January 2002.…”

Section: Methodsmentioning

confidence: 99%

Variability of the Pacific‐Derived Arctic Water Over the Southeastern Wandel Sea Shelf (Northeast Greenland) in 2015–2016

et al. 2019

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A portion of the freshwater transport through Fram Strait consists of low-salinity Pacific-derived Arctic water flowing southward along the east coast of Greenland. The pathways of this water are currently unclear. An Ice Tethered Profiler deployed over the southeastern Wandel Sea shelf (northeast Greenland) in May 2015 collected a profile every 3 hr for a year recording conductivity-temperature-depth (CTD) and Colored Dissolved Organic Matter (CDOM) fluorescence. This was accompanied by velocity observations. The CTD data revealed that the subsurface water (~15-85 m depth) characterized by high CDOM resembles the "cold Halostad" in the Canada Basin formed by the injection of Pacific water. A coastal branch of the Pacific water outflow from the Arctic Ocean supplies the Wandel Sea halostad, which shows a clear seasonal pattern. From July to October-November, the halostad is shallow, more saline, warmer, and with less CDOM. Conversely, from November to April, the halostad deepens, cools, freshens and CDOM increases, likely indicating a higher fraction of Pacific winter water. The CTD surveys, wind and current data, and numerical simulations show that the seasonal variation of wind over the continental slope likely controls seasonal changes of this intermediate water layer. Over northeast Greenland, winter winds have a northerly component from November to April, favoring Ekman transport of the Pacific-derived water to the Wandel Sea shelf. In contrast, the prevailing southerly summer winds result in retreat of the Pacific-derived water off the shelf. The landfast ice off-slope extension modifies wind-forcing disrupting seasonal patterns.Plain Language Summary Arctic climate change is manifested in increased freshening of the surface seawater over recent decades due to increased precipitation, river runoff, and sea-ice and glacier melt. Over the coastal domains of northern Greenland, contributions from glacial melt are superimposed on the low-salinity surface water comprised by river runoff and low-salinity water of Pacific origin, while intermediate water is primarily of Atlantic origin. The glacier meltwater fraction can be significant, but its quantification requires differentiation from the Pacific water, the second largest source of the fresh water in the Arctic Ocean. To date, the Pacific-derived Arctic water component over the Greenland shelves remains poorly studied. The ice-tethered oceanographic mooring deployed over the southeastern Wandel Sea shelf (northeast Greenland) in May 2015 collected oceanographic data for a year. The obtained data and model simulations suggest that the Wandel Sea subsurface layer down to about 80 m depth is supplied by the coastal branch of the Pacific water outflow from the Arctic Ocean. This layer also shows a clear seasonal pattern likely indicating a higher fraction of the Pacific-derived water during winter. The seasonal variation of wind over the continental slope seems to control the Pacific water on-shelf inflow. 2018). In fact, Pacific Water (PW) is the second greatest ...

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Section: Methodsmentioning

confidence: 99%

Variability of the Pacific‐Derived Arctic Water Over the Southeastern Wandel Sea Shelf (Northeast Greenland) in 2015–2016

et al. 2019

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“…This distance is about two-three times less compared to estimates of the first baroclinic Rossby radius of deformation over the Beaufort Sea continental slope (~6-12 km; Nurser and Bacon, 2014), which suggests that the model permits eddies and boundary current instabilities. The sea-ice module used here is the Louvain la-Neuve Ice Model Version 2 with an elasticviscous-plastic rheology (Hunke and Dukowicz, 1997), including both thermodynamic and dynamic components (Fichefet and Maqueda, 1997 Further details, as well as model evaluation, can be found in Hu et al (2018) and Courtois et al (2017). In particular, the model is capable of realistically reproducing water dynamics over the eastern Beaufort Sea continental slope (Figure 3e and f).…”

Section: Research Articlementioning

confidence: 99%

Wind-forced depth-dependent currents over the eastern Beaufort Sea continental slope: Implications for Pacific water transport

Dmitrenko

Kirillov

Myers

et al. 2018

Elementa: Science of the Anthropocene

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Pacific water contributes significantly to the Arctic Ocean freshwater budget. Recent increases in Arctic freshwater flux, also affected by the Pacific-derived Arctic water, impact the Atlantic overturning circulation with implications for global climate. The interannual variability of the Pacific water outflow remains poorly understood, partly due to different branches of the Pacific water flow in the Arctic Ocean. The shelfbreak current over the Beaufort Sea continental slope transports ~50% of the Pacific-derived water eastward along the Beaufort Sea continental slope towards the Canadian Archipelago. The oceanographic mooring deployed over the eastern Beaufort Sea continental slope in October 2003 recorded current velocities through depths of 28–108 m until September 2005. Data analysis revealed that these highly energetic currents have two different modes of depth-dependent behaviour. The downwelling-favourable wind associated with cyclones passing north of the Beaufort Sea continental slope toward the Canadian Archipelago generates depth-intensified shelfbreak currents with along-slope northeastward flow. A surface Ekman on-shore transport and associated increase of the sea surface heights over the shelf produce a cross-slope pressure gradient that drives an along-slope northeastward barotropic flow, in the same direction as the wind. In contrast, the upwelling-favourable wind associated with deep Aleutian Low cyclones over the Alaskan Peninsula and/or Aleutian Island Arc leads to surface-intensified currents with along-slope westward flow. This northeasterly wind generates a surface Ekman transport that moves surface waters offshore. The associated cross-slope pressure gradient drives an along-slope southwestward barotropic flow. The wind-driven barotropic flow generated by upwelling and downwelling is superimposed on the background bottom-intensified shelfbreak current. For downwelling, this flow amplifies the depth-intensified background baroclinic circulation with enhanced Pacific water transport towards the Canadian Archipelago. For upwelling, the shelfbreak current is reversed, which results in surface-intensified flow in the opposite direction. These results are supported by numerical simulations.

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Thermodynamic and Dynamic Ice Thickness Changes in the Canadian Arctic Archipelago in NEMO-LIM2 Numerical Simulations

Cited by 2 publications

References 21 publications

Variability of the Pacific‐Derived Arctic Water Over the Southeastern Wandel Sea Shelf (Northeast Greenland) in 2015–2016

Variability of the Pacific‐Derived Arctic Water Over the Southeastern Wandel Sea Shelf (Northeast Greenland) in 2015–2016

Wind-forced depth-dependent currents over the eastern Beaufort Sea continental slope: Implications for Pacific water transport

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