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

2009 ◽  
Vol 6 (12) ◽  
pp. 3091-3107 ◽  
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 biaises 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 the 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 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 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 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).

scholarly journals Model constraints on the anthropogenic carbon budget of the Arctic Ocean

2019 ◽  
Vol 16 (11) ◽  
pp. 2343-2367 ◽  
Author(s):  
Jens Terhaar ◽  
James C. Orr ◽  
Marion Gehlen ◽  
Christian Ethé ◽  
Laurent Bopp
Keyword(s):  
Ocean Acidification ◽  
Arctic Ocean ◽  
Lower Limit ◽  
Ocean Circulation ◽  
The Arctic ◽  
Model Resolution ◽  
Lateral Transport ◽  
The Arctic Ocean ◽  
Anthropogenic Carbon ◽  
The Difference

Abstract. The Arctic Ocean is projected to experience not only amplified climate change but also amplified ocean acidification. Modeling future acidification depends on our ability to simulate baseline conditions and changes over the industrial era. Such centennial-scale changes require a global model to account for exchange between the Arctic and surrounding regions. Yet the coarse resolution of typical global models may poorly resolve that exchange as well as critical features of Arctic Ocean circulation. Here we assess how simulations of Arctic Ocean storage of anthropogenic carbon (Cant), the main driver of open-ocean acidification, differ when moving from coarse to eddy-admitting resolution in a global ocean-circulation–biogeochemistry model (Nucleus for European Modeling of the Ocean, NEMO; Pelagic Interactions Scheme for Carbon and Ecosystem Studies, PISCES). The Arctic's regional storage of Cant is enhanced as model resolution increases. While the coarse-resolution model configuration ORCA2 (2∘) stores 2.0 Pg C in the Arctic Ocean between 1765 and 2005, the eddy-admitting versions ORCA05 and ORCA025 (1∕2∘ and 1∕4∘) store 2.4 and 2.6 Pg C. The difference in inventory between model resolutions that is accounted for is only from their divergence after 1958, when ORCA2 and ORCA025 were initialized with output from the intermediate-resolution configuration (ORCA05). The difference would have been larger had all model resolutions been initialized in 1765 as was ORCA05. The ORCA025 Arctic Cant storage estimate of 2.6 Pg C should be considered a lower limit because that model generally underestimates observed CFC-12 concentrations. It reinforces the lower limit from a previous data-based approach (2.5 to 3.3 Pg C). Independent of model resolution, there was roughly 3 times as much Cant that entered the Arctic Ocean through lateral transport than via the flux of CO2 across the air–sea interface. Wider comparison to nine earth system models that participated in the Coupled Model Intercomparison Project Phase 5 (CMIP5) reveals much larger diversity of stored Cant and lateral transport. Only the CMIP5 models with higher lateral transport obtain Cant inventories that are close to the data-based estimates. Increasing resolution also enhances acidification, e.g., with greater shoaling of the Arctic's average depth of the aragonite saturation horizon during 1960–2012, from 50 m in ORCA2 to 210 m in ORCA025. Even higher model resolution would likely further improve such estimates, but its prohibitive costs also call for other more practical avenues for improvement, e.g., through model nesting, addition of coastal processes, and refinement of subgrid-scale parameterizations.

Implementation of a multipurpose Arctic Ocean Observing System

2020 ◽  
Author(s):  
Stein Sandven ◽  
Hanne Sagen ◽  
Agnieszka Beszczynska-Möller ◽  
Peter Vo ◽  
Marie-Noelle Houssais ◽  
...  
Keyword(s):  
Arctic Ocean ◽  
Water Column ◽  
The Arctic ◽  
Sea Floor ◽  
Acoustic Thermometry ◽  
The Arctic Ocean ◽  
Global Coverage ◽  
Cable Systems ◽  
Ocean Observing ◽  
Observing Systems

<p>The central Arctic Ocean is one of the least observed oceans in the world. This ice-covered region is challenging for ocean observing with respect to technology, logistics and costs. Many physical, biogeochemical, biological, and geophysical processes in the water column and sea floor under the sea ice are difficult to observe and therefore poorly understood. Today, there are technological advances in platforms and sensors for under-ice observation, which offer possibilities to install and operate sustained observing infrastructures in the Arctic Ocean. The goal of the INTAROS project is to develop integrated observing systems in the Arctic, including improvement of data sharing and dissemination to various user groups. INTAROS supports a number of systems providing data from the ocean in delayed mode as well as in near-real time mode, but only a few operate in the ice-covered areas.</p><p>Autonomous observing platforms used in the ice-free oceans such as Argo floats, gliders, and autonomous surface vehicles cannot yet be used operationally in ice-covered Arctic regions. The limitation is because the sea ice prevents these underwater platforms from reaching the surface for satellite communication and geopositioning. To improve the Arctic Ocean Observing capability OceanObs19 recommended ‘to pilot a sustained multipurpose acoustic network for positioning, tomography, passive acoustics, and communication in an integrated Arctic Observing System, with eventual transition to global coverage’. Acoustic networks have been used locally and regionally in the Arctic for underwater acoustic thermometry, geo-positioning for floats and gliders, and passive acoustic. The Coordinated Arctic Acoustic Thermometry Experiment (CAATEX) is a first step toward developing a basin-scale multipurpose acoustic network using modern instrumentation.</p><p>To provide secure data delivery, submarine cables are needed either as dedicated cabled observatories or as hybrid cable systems (sharing the cable infrastructure between science and commercial telecommunications), or both combined. Several large-scale cabled observatories existing coastal areas in world oceans, but none on the Arctic Ocean. At OceanObs19 it was recommended to transition (telecom+sensing) SMART subsea cable systems from present pilots to trans-ocean implementation, to address climate, ocean circulation, sea level, tsunami and earthquake early warning, ultimately with global coverage. Cabled observatories, either stand alone or branching from a hybrid system, could provide power and real time communication to support connected water column moorings and sea floor instrumentation as well as docking mobile platforms. Subsea cable developers are looking into the possibility to deploy a communication cable across the Arctic Ocean from Europe to Asia, because this offers a much shorter route compared to the terrestrial cables.</p><p> An international consortium of leading scientists in ocean observing with experience in state-of-the-art technologies on platforms, sensors, subsea cable technology, acoustic communication and data transmission plan to establish a project to implement and test the system based on experience from the CAATEX experiment and other Arctic observing system experiments. The INTAROS project is presently developing a Roadmap for an integrated Arctic Observing System, where multipurpose ocean observing systems will be one component.</p>

scholarly journals How well does wind speed predict air-sea gas transfer in the sea ice zone? A synthesis of radon deficit profiles in the upper water column of the Arctic Ocean

2017 ◽  
Vol 122 (5) ◽  
pp. 3696-3714 ◽  
Author(s):  
B. Loose ◽  
R. P. Kelly ◽  
A. Bigdeli ◽  
W. Williams ◽  
R. Krishfield ◽  
...  
Keyword(s):  
Wind Speed ◽  
Sea Ice ◽  
Arctic Ocean ◽  
Water Column ◽  
The Arctic ◽  
Gas Transfer ◽  
The Arctic Ocean

scholarly journals Distribution of Admete contabulata and Iphinopsis inflata in the Arctic (Gastropoda: Cancellariidae)

2018 ◽  
Vol 28 (4) ◽  
pp. 163-168
Author(s):  
I. O. Nekhaev
Keyword(s):  
Arctic Ocean ◽  
The Arctic ◽  
The Pacific ◽  
The Family ◽  
The Arctic Ocean ◽  
Extreme North

Only four species of the family Cancellariidae had been reported from the Arctic. However, known distribution of three of them had been limited to the extreme north of the eastern Atlantic so far. The present paper describes findings of Admete contabulata Friele, 1879 from the Barents and the Kara seas and Iphinopsis inflata (Friele, 1879) from the Pacific part of the Arctic Ocean. Lectotype for Admete contabulata is here designated.

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