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

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.

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

Journal of Glaciology ◽

10.3189/s0022143000034377 ◽

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.

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Atmospheric, oceanic, and sea-ice variability along Nares Strait: a numerical model study

10.5194/egusphere-egu21-12212 ◽

2021 ◽

Author(s):

Yarisbel Garcia Quintana ◽

Paul G. Myers ◽

Kent Moore

Keyword(s):

Numerical Model ◽

Sea Ice ◽

Arctic Ocean ◽

North Atlantic ◽

The Other ◽

The Arctic ◽

Nares Strait ◽

The North ◽

The Arctic Ocean ◽

The North Atlantic

Nares Strait, between Greenland and Ellesmere Island, is one of the main pathways connecting the Arctic Ocean to the North Atlantic. The multi-year sea ice that is transported through the strait plays an important role in the mass balance of Arctic sea-ice as well as influencing the climate of the North Atlantic region. This transport is modulated by the formation of ice arches that form at the southern and northern of the strait.&#160; The arches also play an important role in the maintenance of the North Water Polynya (NOW) that forms at the southern end of the strait. The NOW is one of the largest and most productive of Arctic polynyas.&#160;Given its significance, we use an eddy-permitting regional configuration of the Nucleus for European Modelling of the Ocean (NEMO) to explore sea-ice variability along Nares Strait, from 2002 to 2019.&#160;The model is coupled with the Louvain-la-Neuve (LIM2) sea ice thermodynamic and dynamic numerical model and is forced by the Canadian Meteorological Centre&#8217;s Global Deterministic Prediction System Reforecasts.We use the model to explore the variability in ocean and sea ice characteristics along Nares Strait. The positive and negative degree days, measures of ice decay and growth, along the strait are consistent with the warming that the region is experiencing. Sea-ice production/decay did not show any significant change other than an enhanced decay during the summers of 2017-1019. Sea-ice thickness on the other hand has decreased significantly since 2007. This decrease has been more pronounced along the northern (north of Kane Basin) portion of the strait. What is more, ocean model data indicates that since 2007 the northern Nares Strait upper 100m layer has become fresher, indicating an increase in the freshwater export out of the Arctic Ocean and through the strait. The southern portion of the strait, on the other hand, has become warmer and saltier, which would be consistent with an influx of Irminger Water as proposed by previous modelling results. These changes could impact the formation and stability of the ice arch and hence the cessation of ice transport down Nares Strait as well as contributing to changes in the characteristics of the NOW.&#160;

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

Philosophical Transactions of The Royal Society A Mathematical Physical and Engineering Sciences ◽

10.1098/rsta.2014.0168 ◽

2015 ◽

Vol 373 (2052) ◽

pp. 20140168 ◽

Cited By ~ 9

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.

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Recent behavior of the Nares Strait ice arches: anomalous collapses and enhanced export of multi-year ice from the Arctic Ocean

10.5194/egusphere-egu2020-2425 ◽

2020 ◽

Author(s):

Kent Moore ◽

Stephen Howell ◽

Mike Brady ◽

Xiaoyong Xu ◽

Kaitlin McNeil

Keyword(s):

Sea Ice ◽

Arctic Ocean ◽

The Arctic ◽

Nares Strait ◽

Short Period ◽

The Arctic Ocean ◽

Arctic Ice ◽

Policy Communities ◽

Ice Pack ◽

Area And Volume

The ice arches that usually develop at the northern and southern ends of Nares Strait play an important role in modulating the export of multi-year sea ice out of the Arctic Ocean.&#160;&#160; As a result of global warming, the Arctic Ocean is evolving towards an ice pack that is younger, thinner and more mobile and the fate of its multi-year ice is becoming of increasing interest to both the scientific and policy communities.&#160; Here, we use sea ice motion retrievals derived from Sentinel-1 imagery to report on recent behaviour of these ice arches and the associated ice flux. In addition to the previously identified early collapse of the northern ice arch in May 2017, we report that this arch failed to develop during the winters of 2018 and 2019.&#160; In contrast, we report that the southern ice arch was only present for a short period of time during the winter of 2018.&#160; We also show that the duration of arch formation has decreased over the past 20 years as ice in the region has thinned, while the ice area and volume fluxes have both increased.&#160; These results suggest that a transition is underway towards a state where the formation of these arches will become atypical with a concomitant increase in the export of multi-year ice accelerating the transition towards a younger and thinner Arctic ice pack.

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Hydrographic Changes in Nares Strait (Canadian Arctic Archipelago) in Recent Decades Based on δ18O Profiles of Bivalve Shells

ARCTIC ◽

10.14430/arctic4079 ◽

2011 ◽

Vol 64 (1) ◽

pp. 45 ◽

Cited By ~ 7

Author(s):

Marta E. Torres ◽

Daniela Zima ◽

Kelly K. Falkner ◽

Robie W. Macdonald ◽

Mary O'Brien ◽

...

Keyword(s):

Arctic Ocean ◽

The Arctic ◽

Past Century ◽

Depth Range ◽

Baffin Bay ◽

Nares Strait ◽

The North ◽

The Arctic Ocean ◽

Oxygen Isotopic ◽

Bivalve Shells

Nares Strait is one of three main passages of the Canadian Archipelago that channel relatively fresh seawater from the Arctic Ocean through Baffin Bay to the Labrador Sea. Oxygen isotopic profiles along the growth axis of bivalve shells, collected live over the 5 – 30 m depth range from the Greenland and Ellesmere Island sides of the strait, were used to reconstruct changes in the hydrography of the region over the past century. The variability in oxygen isotope ratios is mainly attributed to variations in salinity and suggests that the northern end of Nares Strait has been experiencing an increase in freshwater runoff since the mid 1980s. The recent changes are most pronounced at the northern end of the strait and diminish toward the south, a pattern consistent with proximity to the apparently freshening Arctic Ocean source in the north and mixing with Baffin Bay waters as the water progresses southward. This increasing freshwater signal may reflect changes in circulation and ice formation that favor an increased flow of relatively fresh waters from the Arctic Ocean into Nares Strait.

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

Earth Planets and Space ◽

10.5047/eps.2010.07.002 ◽

2010 ◽

Vol 62 (10) ◽

pp. 829-832 ◽

Cited By ~ 7

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

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

10.5194/egusphere-egu21-13529 ◽

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

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.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.

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The North Pole Seabed Nature Reserve as a Provisional Arrangement

The International Journal of Marine and Coastal Law ◽

10.1163/157180812x606960 ◽

2012 ◽

Vol 27 (1) ◽

pp. 97-133

Author(s):

Olya Gayazova

Keyword(s):

Continental Shelf ◽

Arctic Ocean ◽

Nature Reserve ◽

North Pole ◽

The Arctic ◽

Median Line ◽

Outer Continental Shelf ◽

The North ◽

The Arctic Ocean ◽

Positive Direct

Abstract That the geographic North Pole is the Arctic Schelling point, is implicit in the Russian submission to the Commission on the Limits of the Continental Shelf. I assess this premise vis-à-vis three other approaches to the outer continental shelf delimitation in the Arctic Ocean—the median-line method; a joint submission; and an international zone around the North Pole—and show that both the premise and the alternatives have limitations. Then I explain how an agreement between the Arctic Ocean states (the A5) to establish a seabed nature reserve north of 88°20´N and within 100 nm from the 2,500-meter isobath overcomes those limitations and what positive direct and indirect effects may come from it.

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Reconstruction of Holocene oceanographic conditions in the Northeastern Baffin Bay

10.5194/cp-2019-152 ◽

2020 ◽

Author(s):

Katrine Elnegaard Hansen ◽

Jacques Giraudeau ◽

Lukas Wacker ◽

Christof Pearce ◽

Marit-Solveig Seidenkrantz

Keyword(s):

Sea Ice ◽

Arctic Ocean ◽

Atlantic Water ◽

The Arctic ◽

Subsurface Water ◽

The Holocene ◽

Baffin Bay ◽

Nares Strait ◽

The Arctic Ocean ◽

Water Conditions

Abstract. The Baffin Bay is a semi-enclosed basin connecting the Arctic Ocean and the western North Atlantic, thus making out a significant pathway for heat exchange. Here we reconstruct the alternating advection of relatively warmer and saline Atlantic waters versus the incursion of colder Arctic water masses entering the Baffin Bay through the multiple gateways in the Canadian Arctic Archipelago and the Nares Strait during the Holocene. We carried out benthic foraminiferal assemblage analyses, X-Ray Fluorescence scanning and radiocarbon dating of a 738 cm long marine sediment core retrieved from the eastern Baffin Bay near Upernavik (Core AMD14-204C; 987m water depth). Results reveal that the eastern Baffin Bay was subjected to several oceanographic changes during the last 9.2 ka BP. Waning deglacial conditions with enhanced meltwater influxes and an extensive sea-ice cover prevailed in the eastern Baffin Bay from 9.2–7.9 ka BP. A transition towards bottom water ameliorations are recorded at 7.9 ka BP by increased advection of Atlantic water masses, encompassing the Holocene Thermal Maximum. A cold period with growing sea-ice cover at 6.7 ka BP interrupts the overall warm subsurface water conditions, promoted by a weaker northward flow of Atlantic waters. The onset of the Neoglaciation at ca. 2.9 ka BP, is marked by an abrupt transition towards a benthic fauna dominated by agglutinated species likely partly explained by a reduction of the influx of Atlantic water, allowing increased influx of the cold, corrosive Baffin Bay Deep Water originating from the Arctic Ocean, to enter the Baffin Bay through the Nares Strait. These cold subsurface water conditions persisted throughout the late Holocene, only interrupted by short-lived warmings superimposed on this cooling trend.

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