Current surges and seabed erosion near the shelf break in the Canadian Beaufort Sea: A response to wind and ice motion stress

Forest, Alexandre; Osborne, Philip D.; Curtiss, Gregory; Lowings, Malcolm G.

doi:10.1016/j.jmarsys.2016.03.008

Cited by 11 publications

(12 citation statements)

References 78 publications

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“…Resuspension of shelf sediments into benthic layers facilitates the lateral transport into the slope and basin. The mechanisms involved in such transport include thermohaline convection (Forest et al, 2007(Forest et al, , 2008(Forest et al, , 2015, current surges (Forest et al, 2007(Forest et al, , 2008(Forest et al, , 2015(Forest et al, , 2016, wind-driven upwelling and downwelling (Forest et al, 2015(Forest et al, , 2016O'Brien et al, 2011), mesoscale eddies (Ashjian et al, 2005;Forest et al, 2008Forest et al, , 2015Kadko et al, 2008;Llinás et al, 2009;Mathis et al, 2007;O'Brien et al, 2011O'Brien et al, , 2013Pickart et al, 2005;Watanabe et al, 2014), and dirty sea ice (e.g., Darby, 2003;Dethleff, 2005;Eicken et al, 1997). Internal waves in the Arctic Ocean can also be of significance locally in transporting particles, such as in the eastern Fram Strait (Sanchez-Vidal et al, 2015), but are weaker compared to those at low latitudes (e.g., D'Asaro & Morison, 1992;Guthrie et al, 2013).…”

Section: Origin Of Lithogenic Particles In the Arctic Oceanmentioning

confidence: 99%

Size‐Fractionated Compositions of Marine Suspended Particles in the Western Arctic Ocean: Lateral and Vertical Sources

Xiang

Lam

2020

JGR Oceans

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We present full water depth sections of size‐fractionated (1–51 μm; >51 μm) concentrations of suspended particulate matter and major particle phase composition (particulate organic matter [POM], including its carbon isotopic composition [POC‐δ13C] and C:N ratio, calcium carbonate [CaCO3], opal, lithogenic particles, and iron and manganese [oxyhydr]oxides) from the U.S. GEOTRACES Arctic Cruise (GN01) in the western Arctic in 2015. Whereas biogenic particles (POM and opal) dominate the upper 1,000 m, lithogenic particles are the most abundant particle type at depth. Minor phases such as manganese (Mn) oxides are higher in GN01 than in any other U.S. GEOTRACES cruises so far. Extremely depleted POC‐δ13C, as low as ~ −32‰, is ubiquitous at the surface of the western Arctic Ocean as a result of different growth rates of phytoplankton. Moderate penetration of depleted POC‐δ13C to depth indicates active sinking of large particles in the central basin. Lateral transport from the Chukchi shelf is also of significance in the western Arctic, as is evident from increases in biogenic silica to POC ratios and Mn oxide concentrations in the halocline, as well as lithogenic element contents in the deep waters. Our study supports previous suggestions of the near absence of CaCO3 in the Arctic Basin. This study presents the first data set of concentration and composition of suspended particles in the western Arctic Ocean and sheds new light on the vertical and lateral processes that govern particle distribution in this enclosed ocean basin.

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Section: Origin Of Lithogenic Particles In the Arctic Oceanmentioning

confidence: 99%

Size‐Fractionated Compositions of Marine Suspended Particles in the Western Arctic Ocean: Lateral and Vertical Sources

Xiang

Lam

2020

JGR Oceans

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“…The background shelfbreak current over the Beaufort Sea continental slope is known to be one of the most energetic features of the Beaufort Sea hydrography (e.g., Nikolopoulos et al, 2009;Dmitrenko et al, 2016;Forest et al, 2016). Along the Alaskan Beaufort Sea slope, the mean shelfbreak current flows eastward as a bottom-intensified shelfbreak jet (e.g., Nikolopoulos et al, 2009; Figure 1a).…”

Section: Introductionmentioning

confidence: 99%

“…Along the Alaskan Beaufort Sea slope, the mean shelfbreak current flows eastward as a bottom-intensified shelfbreak jet (e.g., Nikolopoulos et al, 2009; Figure 1a). Over the Canadian Beaufort Sea slope, the shelfbreak current extends farther east towards the Canadian Archipelago (e.g., Forest et al, 2015Forest et al, , 2016Figure 1a). This current plays an important role in transporting Pacific-derived water entering the Arctic Ocean via Bering Strait.…”

Section: Introductionmentioning

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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“…To explore the similarities and differences in vertical distribution of velocity and SSC in different tidal phases during typical spring tide periods with or without sea ice, we first selected typical spring tide periods based on the changes in tidal current velocity at M1, along with the envelope curve (Figure 5c). These periods were February 2, 3, and 4 (with ice cover), and February 17,18,and 19 (without ice cover). We then performed regression analysis between the velocity and the height from the bottom, as well as between the backscatter intensity and the height from the bottom, in different tidal phases during these typical spring tide periods (high tide, ebb tide, and slack water).…”

Section: Vertical Distribution Of Velocity and Ssc With Or Without Sementioning

confidence: 99%

“…Currently, sea ice research is concentrated in the polar regions [9][10][11][12] but is relatively scant in mid-latitude coastal waters [13][14][15]. Most sea ice studies obtain surface information, such as sea ice coverage area, coverage range, coverage time, and drift trajectory, through satellite remote sensing observations [16][17][18][19][20]. Owing to the limitations of objective conditions (e.g., the performance of instruments and batteries may be greatly reduced in extremely cold weather), very few long-term observations on in situ water bodies demonstrate the vertical hydrodynamic characteristics during sea ice coverage-for instance, the observation of mooring systems conducted by Boone et al in northeast Greenland from October 2013 to May 2014 [21].…”

Section: Introductionmentioning

confidence: 99%

Impact of Sea Ice on the Hydrodynamics and Suspended Sediment Concentration in the Coastal Waters of Qinhuangdao, China

Jiang

Pang

Liu

et al. 2020

Water

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The influence of sea ice on the hydrodynamics, sediment resuspension, and suspended sediment concentration (SSC) in the coastal area of Qinhuangdao was systematically investigated using 45-day in situ measurements at two stations (with ice at station M1 and without ice at station M2) in the Bohai Sea in the winter of 2018. It was found that the daily fluctuations of temperature and salinity at M1 are more significant than those at M2. During a typical seawater icing event on January 28, the temperature and salinity of the bottom water at M1 were decreased by 1.77 °C and increased by 0.4 psu, respectively. Moreover, due to the shielding effect of the sea ice, the residual current was much less affected by the wind at M1 than at M2. For the vertical distribution of current velocity, it changed from a traditional logarithmic type under ice-free conditions to parabolic type under ice-covered conditions due to the larger drag coefficient of the water body on the solid ice surface. For the SSC and turbidity at the bottom layer, the average values were 4.9 μL/L and 8.6 NTU at M1, respectively, approximately half of those at M2. The smaller SSC and turbidity at M1 can be attributed to the lower near-bottom turbulent kinetic energy (TKE). At M2, however, the larger SSC is closely related to the strong wind forcing, which could induce higher TKE without sea ice cover, and hence stronger turbulent resuspension. The seabed sediment analysis results showed that in the study area, fine sand is most likely to resuspend, while cohesive particles would resuspend only under strong hydrodynamic conditions.

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Current surges and seabed erosion near the shelf break in the Canadian Beaufort Sea: A response to wind and ice motion stress

Cited by 11 publications

References 78 publications

Size‐Fractionated Compositions of Marine Suspended Particles in the Western Arctic Ocean: Lateral and Vertical Sources

Size‐Fractionated Compositions of Marine Suspended Particles in the Western Arctic Ocean: Lateral and Vertical Sources

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

Impact of Sea Ice on the Hydrodynamics and Suspended Sediment Concentration in the Coastal Waters of Qinhuangdao, China

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