scholarly journals Hotspots of Dense Water Cascading in the Arctic Ocean: Implications for the Pacific Water Pathways

2020 ◽  
Vol 125 (10) ◽  
Author(s):  
Maria V. Luneva ◽  
Vladimir V. Ivanov ◽  
Fedor Tuzov ◽  
Yevgeny Aksenov ◽  
James D. Harle ◽  
...  
Keyword(s):  
Arctic Ocean ◽  
The Arctic ◽  
Pacific Water ◽  
Dense Water ◽  
The Pacific ◽  
The Arctic Ocean

scholarly journals Export of Arctic freshwater components through the Fram Strait 1998–2010

2012 ◽  
Vol 9 (4) ◽  
pp. 2749-2792
Author(s):  
B. Rabe ◽  
P. Dodd ◽  
E. Hansen ◽  
E. Falck ◽  
U. Schauer ◽  
...  
Keyword(s):  
Arctic Ocean ◽  
The Arctic ◽  
Ice Formation ◽  
Fram Strait ◽  
Pacific Water ◽  
Ice Melt ◽  
The North ◽  
Beaufort Gyre ◽  
The Pacific ◽  
The Arctic Ocean

Abstract. The East Greenland Current in the Western Fram Strait is an important pathway for liquid freshwater export from the Arctic Ocean to the Nordic Seas and the North Atlantic subpolar gyre. We analysed five hydrographic surveys and data from moored current meters around 79° N in the Western Fram Strait between 1998 and 2010. To estimate the composition of southward liquid freshwater transports, inventories of liquid freshwater and components from Dodd et al. (2012) were combined with transport estimates from an inverse model between 10.6° W and 4° E. The southward liquid freshwater transports through the section averaged to 92 mSv (2900 km3 yr−1), relative to a salinity of 34.9. The transports consisted of 123 mSv water from rivers and precipitation (meteoric water), 28 mSv freshwater from the Pacific and 60 mSv freshwater deficit due to brine from ice formation. Variability in liquid freshwater and component transports appear to have been partly due to advection of these water masses to the Fram Strait and partly due to variations in the local volume transport; an exception are Pacific Water transports, which showed little co-variability with volume transports. An increase in Pacific Water transports from 2005 to 2010 suggests a release of Pacific Water from the Beaufort Gyre, in line with an observed expansion of Pacific Water towards the Eurasian Basin. The co-variability of meteoric water and brine from ice formation suggests joint processes in the main sea ice formation regions on the Arctic Ocean shelves. In addition, enhanced levels of sea ice melt observed in 2009 likely led to reduced transports of brine from ice formation. At least part of this additional ice melt appears to have been advected from the Beaufort Gyre and from north of the Bering Strait towards the Fram Strait. The observed changes in liquid freshwater component transports are much larger than known trends in the Arctic liquid freshwater inflow from rivers and the Pacific. Instead, recent observations of an increased storage of liquid freshwater in the Arctic Ocean suggest a decreased export of liquid freshwater. This raises the question how fast the accumulated liquid freshwater will be exported from the Arctic Ocean to the deep water formation regions in the North Atlantic and if an increased export will occur through the Fram Strait.

scholarly journals Arctic Ocean outflow and glacier–ocean interactions modify water over the Wandel Sea shelf (northeastern Greenland)

Ocean Science ◽  
2017 ◽  
Vol 13 (6) ◽  
pp. 1045-1060 ◽  
Author(s):  
Igor A. Dmitrenko ◽  
Sergey A. Kirillov ◽  
Bert Rudels ◽  
David G. Babb ◽  
Leif Toudal Pedersen ◽  
...  
Keyword(s):  
Arctic Ocean ◽  
Continental Slope ◽  
The Arctic ◽  
Ambient Water ◽  
Pacific Water ◽  
The Pacific ◽  
Tidewater Glacier ◽  
The Arctic Ocean ◽  
Water Outflow ◽  
Polar Water

Abstract. The first-ever conductivity–temperature–depth (CTD) observations on the Wandel Sea shelf in northeastern Greenland were collected in April–May 2015. They were complemented by CTDs taken along the continental slope during the Norwegian FRAM 2014–2015 drift. The CTD profiles are used to reveal the origin of water masses and interactions with ambient water from the continental slope and the tidewater glacier outlet. The subsurface water is associated with the Pacific water outflow from the Arctic Ocean. The underlying halocline separates the Pacific water from a deeper layer of polar water that has interacted with the warm Atlantic water outflow through the Fram Strait, recorded below 140 m. Over the outer shelf, the halocline shows numerous cold density-compensated intrusions indicating lateral interaction with an ambient polar water mass across the continental slope. At the front of the tidewater glacier outlet, colder and turbid water intrusions were observed at the base of the halocline. On the temperature–salinity plots these stations indicate a mixing line that is different from the ambient water and seems to be conditioned by the ocean–glacier interaction. Our observations of Pacific water are set within the context of upstream observations in the Beaufort Sea and downstream observations from the Northeast Water Polynya, and clearly show the modification of Pacific water during its advection across the Arctic Ocean. Moreover, ambient water over the Wandel Sea slope shows different thermohaline structures indicating the different origin and pathways of the on-shore and off-shore branches of the Arctic Ocean outflow through the western Fram Strait.

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

Elem Sci Anth ◽  
2018 ◽  
Vol 6 ◽  
Author(s):  
Igor A. Dmitrenko ◽  
Sergei A. Kirillov ◽  
Paul G. Myers ◽  
Alexandre Forest ◽  
Bruno Tremblay ◽  
...  
Keyword(s):  
Pressure Gradient ◽  
Arctic Ocean ◽  
Continental Slope ◽  
Water Transport ◽  
Beaufort Sea ◽  
The Arctic ◽  
Pacific Water ◽  
Barotropic Flow ◽  
The Pacific ◽  
The Arctic Ocean

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.

scholarly journals Arctic Ocean outflow and glacier–ocean interaction modify water over the Wandel Sea shelf, northeast Greenland

2017 ◽  
Author(s):  
Igor A. Dmitrenko ◽  
Sergei A. Kirillov ◽  
Bert Rudels ◽  
David G. Babb ◽  
Leif Toudal Pedersen ◽  
...  
Keyword(s):  
Arctic Ocean ◽  
Continental Slope ◽  
The Arctic ◽  
Fram Strait ◽  
Ambient Water ◽  
Pacific Water ◽  
The Pacific ◽  
The Arctic Ocean ◽  
Water Outflow ◽  
Polar Water

Abstract. The first-ever conductivity–temperature–depth (CTD) observations on the Wandel Sea shelf in North Eastern Greenland were collected in April–May 2015. They were complemented by CTD profiles taken along the continental slope during the Norwegian FRAM 2014–15 drift. The CTD profiles are used to reveal the origin of water masses and interactions with ambient water from the continental slope and the outlet glaciers. The subsurface water is associated with the Pacific Water outflow from the Arctic Ocean. The underlying Halocline separates the Pacific Water from a deeper layer of Polar Water that has interacted with the warm Atlantic water outflow through Fram Strait recorded below 140 m. Over the outer shelf, the Halocline shows numerous cold density-compensated intrusions indicating lateral interaction with an ambient Polar Water mass across the continental slope. At the glacier front, colder and turbid water intrusions were observed at the base of the Halocline. In temperature–salinity space, these data follow a mixing line that diverges from ambient water properties and indicates ocean–glacier interaction. Our observations of Pacific Water are set within the context of upstream observations in the Beaufort Sea and downstream observations from the Northeast Water Polynya and clearly show the modification of Pacific water during its advection across the Arctic Ocean. Moreover, ambient water over the Wandel Sea slope shows different thermohaline structures indicating the different origin and pathways of the on-shore and off-shore branches of the Arctic Ocean outflow through western Fram Strait.

scholarly journals Distribution, fluxes and balance of particulate organic carbon in the Arctic ocean

2019 ◽  
Vol 59 (4) ◽  
pp. 544-552
Author(s):  
A. A. Vetrov ◽  
E. A. Romankevich
Keyword(s):  
Organic Carbon ◽  
Arctic Ocean ◽  
Particulate Organic Carbon ◽  
The Arctic ◽  
Climate Data ◽  
Arctic Seas ◽  
The Pacific ◽  
The Arctic Ocean ◽  
Main Component ◽  
Depth Horizon

Particulate organic carbon (POC) is one of main component of carbon cycle in the Ocean. In this study an attempt to construct a picture of the distribution and fluxes of POC in the Arctic Ocean adjusting for interchange with the Pacific and Atlantic Oceans has been made. The specificity of this construction is associated with an irregular distribution of POC measurements and complicated structure and hydrodynamics of the waters masses. To overcome these difficulties, Multiple Linear Regression technic (MLR) was performed to test the significant relation between POC, temperature, salinity, as well depth, horizon, latitude and offshore distance. The mapping of POC distribution and its fluxes was carrying out at 38 horizons from 5 to 4150 m (resolution 1°×1°). Data on temperature, salinity, meridional and zonal components of current velocities were obtained from ORA S4 database (Integrated Climate Data Center, http://icdc.cen.uni-hamburg.de/las). The import-export of POC between the Arctic, Atlantic and Pacific Oceans as well as between Arctic Seas was precomputed by summer fluxes. The import of POC in the Arctic Ocean is estimated to be 38±8Tg Cyr-1, and the export is -9.5±4.4Tg Cyr-1.

scholarly journals Modelling the effect of boundary scavenging on Thorium and Protactinium profiles in the ocean

2009 ◽  
Vol 6 (4) ◽  
pp. 7853-7896 ◽  
Author(s):  
M. Roy-Barman
Keyword(s):  
Arctic Ocean ◽  
Water Column ◽  
Open Ocean ◽  
The Arctic ◽  
Transport Parameters ◽  
Lateral Transport ◽  
Transport Reaction ◽  
The Pacific ◽  
The Arctic Ocean ◽  
Boundary Scavenging

Abstract. The "boundary scavenging" box model is a cornerstone of our understanding of the particle-reactive radionuclide fluxes between the open ocean and the ocean margins. However, it does not describe the radionuclide profiles in the water column. Here, I present the transport-reaction equations for radionuclides transported vertically by reversible scavenging on settling particles and laterally by horizontal currents between the margin and the open ocean. Analytical solutions of these equations are compared with existing data. In the Pacific Ocean, the model produces "almost" linear 230Th profiles (as observed in the data) despite lateral transport. However, omitting lateral transport biased the 230Th based particle flux estimates by as much as 50%. 231Pa profiles are well reproduced in the whole water column of the Pacific Margin and from the surface down to 3000 m in the Pacific subtropical gyre. Enhanced bottom scavenging or inflow of 231Pa-poor equatorial water may account for the model-data discrepancy below 3000 m. The lithogenic 232Th is modelled using the same transport parameters as 230Th but a different source function. The main source of 232Th scavenged in the open Pacific is advection from the ocean margin, whereas a net flux of 230Th produced in the open Pacific is advected and scavenged at the margin, illustrating boundary exchange. In the Arctic Ocean, the model reproduces 230Th measured profiles that the uni-dimensional scavenging model or the scavenging-ventilation model failed to explain. Moreover, if lateral transport is ignored, the 230Th based particle settling speed may by underestimated by a factor 4 at the Arctic Ocean margin. The very low scavenging rate in the open Arctic Ocean combined with the enhanced scavenging at the margin accounts for the lack of high 231Pa/230Th ratio in arctic sediments.

scholarly journals The Mass Balance of the Sea Ice of the Arctic Ocean

1973 ◽  
Vol 12 (65) ◽  
pp. 173-185 ◽  
Author(s):  
R. M. Koerner
Keyword(s):  
Arctic Ocean ◽  
Ablation Rate ◽  
The Arctic ◽  
First Year ◽  
The North ◽  
Ice Accumulation ◽  
The Pacific ◽  
The Arctic Ocean ◽  
Ridged Ice ◽  
Ice Production

AbstractFrom data taken on the British Trans-Arctic Expedition it is calculated that 9% of the Arctic Ocean surface between the North Pole and Spitsbergen was hummocked or ridged ice, 17% was unridged ice less than a year old, 73% was unridged old ice and 0.6% was ice-free. The mode of 250 thickness measurements taken through level areas of old floes along the entire traverse lies between 2.25 and 2.75 m. The mean end-of-winter thickness of the ice is calculated to be 4.6 m in the Pacific Gyral and 3.9 m in the Trans-Polar Drift Stream. From measurements of the percentage coverage and thickness of the various ice forms, it is calculated that the total annual ice accumulation in the Arctic Ocean is equivalent to a continuous layer of ice 1.1 m thick. 47% of this accumulation occurs in ice-free areas and under ice less than 1 year old. 20% of the total ice production is either directly or indirectly related to ridging or hummocking. An ice-ablation rate of 500 kg m−2 measured on a level area of a multi-year floe is compared with the rate on deformed and ponded ice. Greatest melting occurs on new hummocks and least on old smooth hummocks. The annual balance of ice older than 1 year but younger than multi-year ice is calculated from a knowledge of ice-drift patterns and the percentage coverage of first-year ice. The same calculations give a mean-maximum drift period of 5 years for ice in the Trans-Polar Drift Stream and 16 years in the Pacific Gyral. It is calculated that for the period February 1968 to May 1969 the annual ice export was 5 580 km3.

The Frozen Ocean

PMLA ◽  
2010 ◽  
Vol 125 (3) ◽  
pp. 693-702 ◽  
Author(s):  
Adriana Craciun
Keyword(s):  
Eighteenth Century ◽  
Arctic Ocean ◽  
Native People ◽  
The Arctic ◽  
The Pacific ◽  
The Arctic Ocean

We'll get crushed by the ocean but it will not get us wet.—Isaac Brock, “Invisible” (2007)“There is no Sea With Which Our Age is So Imperfectly Acquainted as the Frozen Ocean,” Wrote the Eighteenth-Century Russian hydrographer Gavriil Sarychev, “and no empire which has more powerful motives and resources for extending its information, in this quarter, than Russia” (iii). Russia's Great Northern Expedition of the 1730s and later expeditions, like Sarychev's in 1785, mapped the shores of the Arctic Ocean across continental Asia, an impressive feat by any century's standards. Meanwhile, the American shores of the Arctic Ocean remained entirely unknown to the European empires (England, France, Spain) most interested in passing to and from the Pacific and Atlantic oceans via the Northwest and Northeast passages. Alexander MacKenzie, Samuel Hearne, and John Franklin, each traveling with native people, walked thousands of miles to reach the Frozen Ocean, leaving in their wake the occasional human disaster and an unimpeachable record of publishing successes, like MacKenzie's Voyages from Montreal to the Frozen Ocean (1801) and Franklin's Narrative of a Journey to the Shores of the Polar Sea (1824).

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