scholarly journals Is ice-rafted sediment in a North Pole marine record evidence for perennial sea-ice cover?

2015 ◽  
Vol 373 (2052) ◽  
pp. 20140168 ◽  
Author(s):  
L. B. Tremblay ◽  
G. A. Schmidt ◽  
S. Pfirman ◽  
R. Newton ◽  
P. DeRepentigny
Keyword(s):  
Sea Ice ◽  
Arctic Ocean ◽  
North American ◽  
Ice Cover ◽  
North Pole ◽  
Wind Forcing ◽  
The Arctic ◽  
Link Type ◽  
The North ◽  
The Arctic Ocean

Ice-rafted sediments of Eurasian and North American origin are found consistently in the upper part (13 Ma BP to present) of the Arctic Coring Expedition (ACEX) ocean core from the Lomonosov Ridge, near the North Pole (≈88° N). Based on modern sea-ice drift trajectories and speeds, this has been taken as evidence of the presence of a perennial sea-ice cover in the Arctic Ocean from the middle Miocene onwards (Krylov et al. 2008 Paleoceanography 23, PA1S06. ( doi:10.1029/2007PA001497 ); Darby 2008 Paleoceanography 23, PA1S07. ( doi:10.1029/2007PA001479 )). However, other high latitude land and marine records indicate a long-term trend towards cooling broken by periods of extensive warming suggestive of a seasonally ice-free Arctic between the Miocene and the present (Polyak et al. 2010 Quaternary Science Reviews 29, 1757–1778. ( doi:10.1016/j.quascirev.2010.02.010 )). We use a coupled sea-ice slab-ocean model including sediment transport tracers to map the spatial distribution of ice-rafted deposits in the Arctic Ocean. We use 6 hourly wind forcing and surface heat fluxes for two different climates: one with a perennial sea-ice cover similar to that of the present day and one with seasonally ice-free conditions, similar to that simulated in future projections. Model results confirm that in the present-day climate, sea ice takes more than 1 year to transport sediment from all its peripheral seas to the North Pole. However, in a warmer climate, sea-ice speeds are significantly faster (for the same wind forcing) and can deposit sediments of Laptev, East Siberian and perhaps also Beaufort Sea origin at the North Pole. This is primarily because of the fact that sea-ice interactions are much weaker with a thinner ice cover and there is less resistance to drift. We conclude that the presence of ice-rafted sediment of Eurasian and North American origin at the North Pole does not imply a perennial sea-ice cover in the Arctic Ocean, reconciling the ACEX ocean core data with other land and marine records.

scholarly journals Interpretation of Slar Imagery of Sea Ice in Nares Strait and the Arctic Ocean

1975 ◽  
Vol 15 (73) ◽  
pp. 193-213
Author(s):  
Moira Dunbar
Keyword(s):  
Sea Ice ◽  
Arctic Ocean ◽  
North Pole ◽  
The Arctic ◽  
Canadian Forces ◽  
Nares Strait ◽  
The North ◽  
The Arctic Ocean ◽  
Ice Edge ◽  
Airborne Sensors

AbstractSLAR imagery of Nares Strait was obtained on three flights carried out in. January, March, and August of 1973 by Canadian Forces Maritime Proving and Evaluation Unit in an Argus aircraft equipped with a Motorola APS-94D SLAR; the March flight also covered two lines in the Arctic Ocean, from Alert 10 the North Pole and from the Pole down the long. 4ºE. meridian to the ice edge at about lat. 80º N. No observations on the ground were possible, but -some back-up was available on all flights from visual observations recorded in the air, and on the March flight from infrared line-scan and vertical photography.The interpretation of ice features from the SLAR imagery is discussed, and the conclusion reached that in spite of certain ambiguities the technique has great potential which will increase with improving resolution, Extent of coverage per distance flown and independence of light and cloud conditions make it unique among airborne sensors.

scholarly journals Interpretation of Slar Imagery of Sea Ice in Nares Strait and the Arctic Ocean

1975 ◽  
Vol 15 (73) ◽  
pp. 193-213 ◽  
Author(s):  
Moira Dunbar
Keyword(s):  
Sea Ice ◽  
Arctic Ocean ◽  
North Pole ◽  
The Arctic ◽  
Canadian Forces ◽  
Nares Strait ◽  
The North ◽  
The Arctic Ocean ◽  
Ice Edge ◽  
Airborne Sensors

Abstract SLAR imagery of Nares Strait was obtained on three flights carried out in. January, March, and August of 1973 by Canadian Forces Maritime Proving and Evaluation Unit in an Argus aircraft equipped with a Motorola APS-94D SLAR; the March flight also covered two lines in the Arctic Ocean, from Alert 10 the North Pole and from the Pole down the long. 4ºE. meridian to the ice edge at about lat. 80º N. No observations on the ground were possible, but -some back-up was available on all flights from visual observations recorded in the air, and on the March flight from infrared line-scan and vertical photography. The interpretation of ice features from the SLAR imagery is discussed, and the conclusion reached that in spite of certain ambiguities the technique has great potential which will increase with improving resolution, Extent of coverage per distance flown and independence of light and cloud conditions make it unique among airborne sensors.

Drivers of sea ice decline in the Fram Strait and north of Svalbard 

2021 ◽  
Author(s):  
Agata Grynczel ◽  
Agnieszka Beszczynska-Moeller ◽  
Waldemar Walczowski
Keyword(s):  
Sea Ice ◽  
Arctic Ocean ◽  
Ice Cover ◽  
Atlantic Water ◽  
The Arctic ◽  
Fram Strait ◽  
Atmospheric Conditions ◽  
The North ◽  
The Arctic Ocean ◽  
Atlantic Origin

<p>The Arctic Ocean is undergoing rapid change. Satellite observations indicate significant negative Arctic sea ice extent trends in all months and substantial reduction of winter sea ice in the Atlantic sector. One of the possible reasons can be sought in the observed warming of Atlantic water, carried through Fram Strait into the Arctic Ocean. Fram Strait, as well as the region north of Svalbard, play a key role in controlling the amount of oceanic heat supplied to the Arctic Ocean and are the place of dynamic interaction between the ocean and sea ice. Shrinking sea ice cover in the southern part of Nansen Basin (north of Svalbard) and shifting the ice edge in Fram Strait are driven by the interplay between increased advection of oceanic heat in the Atlantic origin water and changes in the local atmospheric conditions.</p><p>Processes related to the loss of sea ice and the upward transport of heat from the layers of the Arctic Ocean occupied by the Atlantic water are still not fully explored, but higher than average temperature of Atlantic inflow in the Nordic Seas influence the upper ocean stratification and ice cover in the Arctic Ocean, in particular in the north of Svalbard area. The regional sea ice cover decline is statistically signifcant in all months, but the largest changes in the Nansen Basin are observed in winter season. The winter sea ice loss north of Svalbard is most pronounced above the core of the inflow warm Atlantic water. The basis for this hypothesis of the research is that continuously shrinking sea ice cover in the region north of Svalbard and withdrawal of the sea ice cover towards the northeast are driven by the interplay between increased oceanic heat in the Atlantic origin water and changes in the local atmospheric conditions, that can result in the increased ocean-air-sea ice exchange in winter seasons. In the current study we describe seasonal, interannual and decadal variability of concentration, drift, and thickness of sea ice in two regions, the north of Svalbard and central part of the Fram Strait, based on the satellite observations. To analyze the observed changes in the sea ice cover in relation to Atlantic water variability and atmospheric forcing we employ hydrographic data from the repeated CTD sections and new atmospheric reanalysis from ERA5. Atlantic water variability is described based on the set of summer synoptic sections across the Fram Strait branch of the Atlantic inflow that have been occupied annually since 1996 under the long-term observational program AREX of the Institute of Oceanology PAS. To elucidate driving mechanisms of the sea ice cover changes observed in different seasons in Fram Strait and north of Svalbard we analyze changes in the temperature, heat content and transport of the Atlantic water and describe their potential links to variable atmospheric forcing, including air temperature, air-ocean fluxes, and changes in wind pattern and wind stress.</p>

Impact of Atlantic water variability on sea ice changes in the Fram Strait and north of Svalbard

2020 ◽  
Author(s):  
Agata Grynczel ◽  
Agnieszka Beszczynska-Moeller ◽  
Waldemar Walczowski
Keyword(s):  
Sea Ice ◽  
Arctic Ocean ◽  
Ice Cover ◽  
Atlantic Water ◽  
The Arctic ◽  
Fram Strait ◽  
Atlantic Sector ◽  
The North ◽  
The Arctic Ocean ◽  
West Spitsbergen

<p>Recent satellite passive microwave observations indicate significant negative Arctic sea ice extent trends in all months and substantial reduction of winter sea ice in the Atlantic sector. Warm and salty oceanic water masses from the North Atlantic flow towards the Arctic Ocean along the eastern Fram Strait, carried by the West Spitsbergen Current (WSC). Fram Strait, as well as the region north of Svalbard, play a key role in controlling the amount of oceanic heat supplied to the Arctic Ocean and are the place of dynamic interaction between the ocean and sea ice. The north of Svalbard area is one of the regions where the substantial changes in sea ice concentrations are observed both in summer and in winter. One of the possible reasons can be sought in the observed warming of Atlantic water, carried through Fram Strait into the Arctic Ocean. The main goal of this work is to analyse and explain the sea ice variability along main pathways of the Atlantic origin water (AW) in the context of observed warming of Atlantic water layer. Shrinking sea ice cover in the southern part of Nansen Basin (north of Svalbard) and shifting the ice edge in Fram Strait are driven by the interplay between increased advection of oceanic heat in the Atlantic origin water and changes in the local atmospheric conditions that result in the increased ocean-air-sea ice exchange in winter seasons. The basis for this hypothesis is warming of winter mean surface air temperature observed north of Svalbard and withdrawal of the sea ice cover towards the northeast, along with the pathways of water inflow in the Atlantic sector of the Arctic Ocean. Hydrographic data from vertical CTD profiles were collected during annual summer expeditions of the research vessel "Oceania", conducted in Fram Strait and the southern part of the Nansen Basin over the past two decades. The measurement strategy of the original research program AREX, which consists of the performance of cross-sections perpendicular to the presumed direction of the West Spitsbergen Current, allowed to observe changes in the properties and transport of the Atlantic Water carried to the Arctic Ocean. The analysis of past and present changes in the sea ice cover in relation to Atlantic water variability and atmospheric forcing employs hydrographic data from the repeated CTD sections, systematically collected since 1996 during annual summer Arctic long-term monitoring program AREX, satellite products of sea ice concentration and drift, and selected reanalysis data sets.</p>

scholarly journals A 21 year record of Arctic sea-ice extents and their regional, seasonal and monthly variability and trends

2002 ◽  
Vol 34 ◽  
pp. 441-446 ◽  
Author(s):  
Claire L. Parkinson ◽  
Donald J. Cavalieri
Keyword(s):  
Sea Ice ◽  
Arctic Ocean ◽  
Ice Cover ◽  
Arctic Sea Ice ◽  
The Arctic ◽  
Monthly Basis ◽  
The North ◽  
Yearly Average ◽  
The Arctic Ocean ◽  
North Polar

AbstractSatellite passive-microwave data have been used to calculate sea-ice extents over the period 1979–99 for the north polar sea-ice cover as a whole and for each of nine regions. Over this 21 year time period, the trend in yearly-average ice extents for the ice cover as a whole is –32 900±6100 km2 a–1 (–2.7 ±0.5% per decade), indicating a statistically significant reduction in sea-ice coverage. Regionally, the reductions are greatest in the Arctic Ocean, the Kara and Barents Seas and the Seas of Okhotsk and Japan; and seasonally, the reductions are greatest in summer, for which season the 1979–99 trend in ice extents is –41600±12 900 km2 a–1 (–4.9±1.5% per decade). On a monthly basis, the reductions are greatest in July and September for the north polar ice cover as a whole, in September for the Arctic Ocean, in June and July for the Kara and Barents Seas, and in April for the Seas of Okhotsk and Japan. Of the nine regions, only the Bering Sea and the Gulf of St Lawrence show positive ice-extent trends on a yearly-average basis. However, the increases in these two regions are not statistically significant. For the north polar region as a whole, and for the Arctic Ocean, the Seas of Okhotsk and Japan, and Hudson Bay, the negative trends in the yearly averages are statistically significant at a 99% confidence level.

Increasing Multiyear Sea Ice Loss in the Beaufort Sea: A New Export Pathway for the Diminishing Multiyear Ice Cover of the Arctic Ocean

2021 ◽  
Author(s):  
David Gareth Babb ◽  
Ryan J. Galley ◽  
Stephen E. L. Howell ◽  
Jack Christopher Landy ◽  
Julienne Christine Stroeve ◽  
...  
Keyword(s):  
Sea Ice ◽  
Arctic Ocean ◽  
Beaufort Sea ◽  
Ice Cover ◽  
The Arctic ◽  
Export Pathway ◽  
The Arctic Ocean ◽  
Multiyear Ice

scholarly journals Impact of Variable Atmospheric and Oceanic Form Drag on Simulations of Arctic Sea Ice*

2014 ◽  
Vol 44 (5) ◽  
pp. 1329-1353 ◽  
Author(s):  
Michel Tsamados ◽  
Daniel L. Feltham ◽  
David Schroeder ◽  
Daniela Flocco ◽  
Sinead L. Farrell ◽  
...  
Keyword(s):  
Sea Ice ◽  
Arctic Ocean ◽  
Ice Cover ◽  
Arctic Sea Ice ◽  
The Arctic ◽  
Form Drag ◽  
Drag Coefficients ◽  
Arctic Sea ◽  
The Arctic Ocean ◽  
Range Of Values

Abstract Over Arctic sea ice, pressure ridges and floe and melt pond edges all introduce discrete obstructions to the flow of air or water past the ice and are a source of form drag. In current climate models form drag is only accounted for by tuning the air–ice and ice–ocean drag coefficients, that is, by effectively altering the roughness length in a surface drag parameterization. The existing approach of the skin drag parameter tuning is poorly constrained by observations and fails to describe correctly the physics associated with the air–ice and ocean–ice drag. Here, the authors combine recent theoretical developments to deduce the total neutral form drag coefficients from properties of the ice cover such as ice concentration, vertical extent and area of the ridges, freeboard and floe draft, and the size of floes and melt ponds. The drag coefficients are incorporated into the Los Alamos Sea Ice Model (CICE) and show the influence of the new drag parameterization on the motion and state of the ice cover, with the most noticeable being a depletion of sea ice over the west boundary of the Arctic Ocean and over the Beaufort Sea. The new parameterization allows the drag coefficients to be coupled to the sea ice state and therefore to evolve spatially and temporally. It is found that the range of values predicted for the drag coefficients agree with the range of values measured in several regions of the Arctic. Finally, the implications of the new form drag formulation for the spinup or spindown of the Arctic Ocean are discussed.

scholarly journals A new aeromagnetic survey of the North Pole and the Arctic Ocean north of Greenland and Ellesmere Island

2010 ◽  
Vol 62 (10) ◽  
pp. 829-832 ◽  
Author(s):  
Jürgen Matzka ◽  
Thorkild M. Rasmussen ◽  
Arne V. Olesen ◽  
Jens Emil Nielsen ◽  
Rene Forsberg ◽  
...  
Keyword(s):  
Arctic Ocean ◽  
Ellesmere Island ◽  
North Pole ◽  
The Arctic ◽  
Aeromagnetic Survey ◽  
The North ◽  
The Arctic Ocean

scholarly journals Laboratory experiments on Internal Solitary Waves in ice covered waters 

2021 ◽  
Author(s):  
Magda Carr ◽  
Peter Sutherland ◽  
Andrea Haase ◽  
Karl-Ulrich Evers ◽  
Ilker Fer ◽  
...  
Keyword(s):  
Sea Ice ◽  
Arctic Ocean ◽  
Solitary Waves ◽  
Ice Cover ◽  
The Arctic ◽  
Internal Solitary Waves ◽  
Small Scale ◽  
Lower Bounding ◽  
The Arctic Ocean ◽  
Wave Induced

<p>Oceanic internal waves (IWs) propagate along density interfaces and are ubiquitous in stratified water. Their properties are influenced strongly by the nature and form of the upper and lower bounding surfaces of the containing basin(s) in which they propagate.<span>  </span>As the Arctic Ocean evolves to a seasonally more ice-free state, the IW field will be affected by the change. The relationship between IW dynamics and ice is important in understanding (i) the general circulation and thermodynamics in the Arctic Ocean and (ii) local mixing processes that supply heat and nutrients from depth into upper layers, especially the photic zone. This, in turn, has important ramifications for sea ice formation processes and the state of local and regional ecosystems.<span>  </span>Despite this, the effect of diminishing sea ice cover on the IW field (and vice versa) is not well established. A better understanding of IW dynamics in the Arctic Ocean and, in particular, how the IW field is affected by changes in both ice cover and stratification, is central in understanding how the rapidly changing Arctic will adapt to climate change.</p><p> </p><p>An experimental study of internal solitary waves (ISWs) propagating in a stably stratified two-layer fluid in which the upper boundary condition changes from open water to ice are studied for grease, level, and nilas ice. The experiments show that the internal wave-induced flow at the surface is capable of transporting sea-ice in the horizontal direction. In the level ice case, the transport speed of, relatively long ice floes, nondimensionalized by the wave speed is linearly dependent on the length of the ice floe nondimensionalized by the wave length. It will also be shown that bottom roughness associated with different ice types can cause varying degrees of vorticity and small-scale turbulence in the wave-induced boundary layer beneath the ice. Measures of turbulent kinetic energy dissipation under the ice are shown to be comparable to those at the wave density interface. Moreover, in cases where the ice floe protrudes into the pycnocline, interaction with the ice edge can cause the ISW to break or even be destroyed by the process. The results suggest that interaction between ISWs and sea ice may be an important mechanism for dissipation of ISW energy in the Arctic Ocean.</p><p> </p><p><strong>Acknowledgements</strong></p><p>This work was funded through the EU Horizon 2020 Research and Innovation Programme Hydralab+.</p>

scholarly journals A Benchmark for Trace Greenhouse Gases in the Arctic Ocean

Eos ◽  
2017 ◽  
Author(s):  
Terri Cook
Keyword(s):  
Nitrous Oxide ◽  
Greenhouse Gases ◽  
Arctic Ocean ◽  
North American ◽  
The Arctic ◽  
The North ◽  
The Arctic Ocean ◽  
North American Arctic

Samples of seawater from the North American Arctic show that the region is neither a major source nor sink of methane and nitrous oxide to the overlying atmosphere.

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