Dinocyst-based reconstructions of sea ice cover concentration during the Holocene in the Arctic Ocean, the northern North Atlantic Ocean and its adjacent seas

2013 ◽  
Vol 79 ◽  
pp. 111-121 ◽  
Author(s):  
Anne de Vernal ◽  
Claude Hillaire-Marcel ◽  
André Rochon ◽  
Bianca Fréchette ◽  
Maryse Henry ◽  
...  
Keyword(s):  
Atlantic Ocean ◽  
Sea Ice ◽  
Arctic Ocean ◽  
North Atlantic ◽  
North Atlantic Ocean ◽  
Ice Cover ◽  
The Arctic ◽  
The Holocene ◽  
The Arctic Ocean

scholarly journals Unprecedented decline of Arctic sea ice outflow in 2018

2021 ◽  
Author(s):  
Hiroshi Sumata ◽  
Laura de Steur ◽  
Sebastian Gerland ◽  
Dmitry Divine ◽  
Olga Pavlova
Keyword(s):  
Atlantic Ocean ◽  
Sea Ice ◽  
Arctic Ocean ◽  
North Atlantic ◽  
North Atlantic Ocean ◽  
Arctic Sea Ice ◽  
The Arctic ◽  
Fram Strait ◽  
Atlantic Sector ◽  
The Arctic Ocean

Abstract Fram Strait is the major gateway connecting the Arctic Ocean and North Atlantic Ocean, where nearly 90% of the sea ice export from the Arctic Ocean takes place. The exported sea ice is a large source of freshwater to the Nordic Seas and Subpolar North Atlantic, thereby preconditioning European climate and deep water formation in the downstream North Atlantic Ocean. Here we show that in 2018, the ice export through Fram Strait showed an unprecedented decline since the early 1990s. The 2018 ice export was reduced to less than 40% relative to that between 2000 and 2017, and amounted to just 25% of the 1990s. The minimum export was attributed to regional sea ice-ocean processes driven by an anomalous atmospheric circulation over the Atlantic sector of the Arctic. The anomalous circulation caused a stagnation of southward sea ice drift, causing a sudden drop of sea ice thickness north of the Fram Strait due to local heat supply from the ocean. The result indicates that a drastic change of the freshwater cycle and its environmental consequences happen not only through ongoing Arctic-wide ice thinning, but also by regional scale atmospheric anomalies in the Atlantic sector on annual timescales.

scholarly journals Cooling down the world oceans and the earth by enhancing the North Atlantic Ocean current

2019 ◽  
Vol 2 (1) ◽  
Author(s):  
Julian David Hunt ◽  
Andreas Nascimento ◽  
Fabio A. Diuana ◽  
Natália de Assis Brasil Weber ◽  
Gabriel Malta Castro ◽  
...  
Keyword(s):  
Atlantic Ocean ◽  
Arctic Ocean ◽  
North Atlantic ◽  
North Atlantic Ocean ◽  
The Arctic ◽  
Ocean Current ◽  
The North ◽  
The Arctic Ocean ◽  
Albedo Effect ◽  
Arctic Atmosphere

AbstractThe world is going through intensive changes due to global warming. It is well known that the reduction in ice cover in the Arctic Ocean further contributes to increasing the atmospheric Arctic temperature due to the reduction of the albedo effect and increase in heat absorbed by the ocean’s surface. The Arctic ice cover also works like an insulation sheet, keeping the heat in the ocean from dissipating into the cold Arctic atmosphere. Increasing the salinity of the Arctic Ocean surface would allow the warmer and less salty North Atlantic Ocean current to flow on the surface of the Arctic Ocean considerably increasing the temperature of the Arctic atmosphere and release the ocean heat trapped under the ice. This paper argues that if the North Atlantic Ocean current could maintain the Arctic Ocean ice-free during the winter, the longwave radiation heat loss into space would be larger than the increase in heat absorption due to the albedo effect. This paper presents details of the fundamentals of the Arctic Ocean circulation and presents three possible approaches for increasing the salinity of the surface water of the Arctic Ocean. It then discusses that increasing the salinity of the Arctic Ocean would warm the atmosphere of the Arctic region, but cool down the oceans and possibly the Earth. However, it might take thousands of years for the effects of cooling the oceans to cool the global average atmospheric temperature.

scholarly journals The Arctic sea ice cover of 2016: a year of record-low highs and higher-than-expected lows

2018 ◽  
Vol 12 (2) ◽  
pp. 433-452 ◽  
Author(s):  
Alek A. Petty ◽  
Julienne C. Stroeve ◽  
Paul R. Holland ◽  
Linette N. Boisvert ◽  
Angela C. Bliss ◽  
...  
Keyword(s):  
Sea Ice ◽  
Arctic Ocean ◽  
North Atlantic ◽  
Ice Cover ◽  
Arctic Sea Ice ◽  
The Arctic ◽  
Sea Ice Extent ◽  
Atlantic Sector ◽  
Arctic Sea ◽  
The Arctic Ocean

Abstract. The Arctic sea ice cover of 2016 was highly noteworthy, as it featured record low monthly sea ice extents at the start of the year but a summer (September) extent that was higher than expected by most seasonal forecasts. Here we explore the 2016 Arctic sea ice state in terms of its monthly sea ice cover, placing this in the context of the sea ice conditions observed since 2000. We demonstrate the sensitivity of monthly Arctic sea ice extent and area estimates, in terms of their magnitude and annual rankings, to the ice concentration input data (using two widely used datasets) and to the averaging methodology used to convert concentration to extent (daily or monthly extent calculations). We use estimates of sea ice area over sea ice extent to analyse the relative “compactness” of the Arctic sea ice cover, highlighting anomalously low compactness in the summer of 2016 which contributed to the higher-than-expected September ice extent. Two cyclones that entered the Arctic Ocean during August appear to have driven this low-concentration/compactness ice cover but were not sufficient to cause more widespread melt-out and a new record-low September ice extent. We use concentration budgets to explore the regions and processes (thermodynamics/dynamics) contributing to the monthly 2016 extent/area estimates highlighting, amongst other things, rapid ice intensification across the central eastern Arctic through September. Two different products show significant early melt onset across the Arctic Ocean in 2016, including record-early melt onset in the North Atlantic sector of the Arctic. Our results also show record-late 2016 freeze-up in the central Arctic, North Atlantic and the Alaskan Arctic sector in particular, associated with strong sea surface temperature anomalies that appeared shortly after the 2016 minimum (October onwards). We explore the implications of this low summer ice compactness for seasonal forecasting, suggesting that sea ice area could be a more reliable metric to forecast in this more seasonal, “New Arctic”, sea ice regime.

scholarly journals A multi-model CMIP6-PMIP4 study of Arctic sea ice at 127 ka: sea ice data compilation and model differences

2021 ◽  
Vol 17 (1) ◽  
pp. 37-62 ◽  
Author(s):  
Masa Kageyama ◽  
Louise C. Sime ◽  
Marie Sicard ◽  
Maria-Vittoria Guarino ◽  
Anne de Vernal ◽  
...  
Keyword(s):  
Sea Ice ◽  
Arctic Ocean ◽  
North Atlantic ◽  
Ice Cover ◽  
Arctic Sea Ice ◽  
The Arctic ◽  
Nordic Seas ◽  
Arctic Sea ◽  
The Arctic Ocean ◽  
Intercomparison Project

Abstract. The Last Interglacial period (LIG) is a period with increased summer insolation at high northern latitudes, which results in strong changes in the terrestrial and marine cryosphere. Understanding the mechanisms for this response via climate modelling and comparing the models' representation of climate reconstructions is one of the objectives set up by the Paleoclimate Modelling Intercomparison Project for its contribution to the sixth phase of the Coupled Model Intercomparison Project. Here we analyse the results from 16 climate models in terms of Arctic sea ice. The multi-model mean reduction in minimum sea ice area from the pre industrial period (PI) to the LIG reaches 50 % (multi-model mean LIG area is 3.20×106 km2, compared to 6.46×106 km2 for the PI). On the other hand, there is little change for the maximum sea ice area (which is 15–16×106 km2 for both the PI and the LIG. To evaluate the model results we synthesise LIG sea ice data from marine cores collected in the Arctic Ocean, Nordic Seas and northern North Atlantic. The reconstructions for the northern North Atlantic show year-round ice-free conditions, and most models yield results in agreement with these reconstructions. Model–data disagreement appear for the sites in the Nordic Seas close to Greenland and at the edge of the Arctic Ocean. The northernmost site with good chronology, for which a sea ice concentration larger than 75 % is reconstructed even in summer, discriminates those models which simulate too little sea ice. However, the remaining models appear to simulate too much sea ice over the two sites south of the northernmost one, for which the reconstructed sea ice cover is seasonal. Hence models either underestimate or overestimate sea ice cover for the LIG, and their bias does not appear to be related to their bias for the pre-industrial period. Drivers for the inter-model differences are different phasing of the up and down short-wave anomalies over the Arctic Ocean, which are associated with differences in model albedo; possible cloud property differences, in terms of optical depth; and LIG ocean circulation changes which occur for some, but not all, LIG simulations. Finally, we note that inter-comparisons between the LIG simulations and simulations for future climate with moderate (1 % yr−1) CO2 increase show a relationship between LIG sea ice and sea ice simulated under CO2 increase around the years of doubling CO2. The LIG may therefore yield insight into likely 21st century Arctic sea ice changes using these LIG simulations.

Non-steady behaviour in the Cenozoic polar North Atlantic system: the onset and variability of Northern Hemisphere glaciations

1995 ◽  
Vol 352 (1699) ◽  
pp. 373-385 ◽  
Keyword(s):  
Sea Ice ◽  
Arctic Ocean ◽  
Northern Hemisphere ◽  
North Atlantic ◽  
Middle Miocene ◽  
Ice Cover ◽  
The Arctic ◽  
Past Century ◽  
The Past ◽  
The Arctic Ocean

Changes of the extent of the Arctic Ocean sea-ice cover over the past century, the geological record of the Arctic Ocean seafloor of the youngest geological past, as well as the evidence of a pre-Glacial temperate to warm Arctic Ocean during Mesozoic and Palaeogene time are witnesses of dramatic revolutions of the Arctic oceanography. The climate over northwestern Europe on a regional scale as well as the global environment have responded to these revolutions instantly over geological time scales. Results of ocean drilling in the deep northern North Atlantic document an onset of Northern Hemisphere glaciation towards the end of the middle Miocene (10-14 Ma). While the available evidence points to early glaciations of modest extent and intensity centred around southern Greenland, the early to mid-Pliocene intervals record a sudden intensification of ice-rafting in the Labrador and Norwegian Greenland seas as well as in the Arctic Ocean proper. The Greenland ice cap seems to have remained rather stable whereas the northwest European ice shields have experienced rapid and dramatic changes leading to their frequent complete destruction. Many sediment properties seem to suggest that orbital parameters (Milankovitch-frequencies) and their temporal variability control important properties of the deep-sea floor depositional environment. Obliquity (with approximately 40 ka) seems to be dominant in pre-Glacial (middle Miocene) as well as Glacial (post late Miocene) scenarios whereas eccentricity (with approximately 100 ka) only dominated the past 600-800 ka. PlioPleistocene deposits of the Arctic Ocean proper, of the entire Norwegian Greenland and of the Labrador seas have recorded the almost continuous presence of sea-ice cover with only short ‘interglacial’ intervals when the eastern Norwegian Sea was ice-free. The documentation of long-term changes of the oceanographic and climatic properties of the Arctic environments recorded in the sediment cover of the deepsea floors might also serve to explain scenarios which have no modern analog, but which might well develop in the future under the influence of the anthropogenic drift towards warmer global climates.

scholarly journals The Arctic sea ice cover of 2016: A year of record low highs and higher than expected lows

2017 ◽  
Author(s):  
Alek A. Petty ◽  
Julienne C. Stroeve ◽  
Paul R. Holland ◽  
Linette N. Boisvert ◽  
Angela C. Bliss ◽  
...  
Keyword(s):  
Sea Ice ◽  
Arctic Ocean ◽  
North Atlantic ◽  
Ice Cover ◽  
Arctic Sea Ice ◽  
The Arctic ◽  
Sea Ice Extent ◽  
Arctic Sea ◽  
The Arctic Ocean ◽  
Arctic Sea Ice Extent

Abstract. 2016 was an interesting year in the Arctic, with record low sea ice at the start of the year, but a summer (September) Arctic sea ice extent that was higher than expected by most seasonal forecasts. Here we explore the 2016 Arctic sea ice state in terms of its monthly sea ice cover, placing this in context of the sea ice conditions observed since 2000. We demonstrate the sensitivity of monthly Arctic sea ice extent and area estimates, in terms of their magnitude and annual rankings, to the ice concentration input data (using two widely used datasets) and to the methodology used to convert concentration to extent (daily or monthly extent calculations). We use estimates of sea ice area to analyse the relative 'compactness' of the Arctic sea ice cover, highlighting anomalously low compactness in the summer of 2016 which contributed to the higher than expected September ice extent. Two cyclones that entered the Arctic Ocean during August appear to have driven this low concentration/compactness ice cover, but were not sufficient to cause more widespread melt out and a new record low September ice extent. We use concentration budgets to explore the regions and processes (thermodynamics/dynamics) contributing to the monthly 2016 extent/area estimates highlighting, amongst other things, rapid ice intensification across the central eastern Arctic through September. Two different products show significant early melt onset across the Arctic Ocean in 2016, including record early melt onset in the North Atlantic sector of the Arctic. Our results also show record late 2016 freeze up in the Central Arctic, North Atlantic. and the Alaskan Arctic sector in particular, associated with strong sea surface temperature anomalies that appeared shortly after the 2016 minimum (October onwards). We explore the implications of this low summer ice compactness for seasonal forecasting, suggesting that sea ice area could be a more reliable metric to forecast in this more seasonal, 'New Arctic', sea ice regime.

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

Separating the influences of low-latitude warming and sea-ice loss on Northern Hemisphere climate change

2022 ◽  
pp. 1-59
Author(s):  
Paul J. Kushner ◽  
Russell Blackport ◽  
Kelly E. McCusker ◽  
Thomas Oudar ◽  
Lantao Sun ◽  
...  
Keyword(s):  
Sea Ice ◽  
Arctic Ocean ◽  
Northern Hemisphere ◽  
North Atlantic ◽  
High Latitude ◽  
North Pacific ◽  
Heat Fluxes ◽  
The Arctic ◽  
Low Latitude ◽  
The Arctic Ocean

Abstract Analyzing a multi-model ensemble of coupled climate model simulations forced with Arctic sea-ice loss using a two-parameter pattern-scaling technique to remove the cross-coupling between low- and high-latitude responses, the sensitivity to high-latitude sea-ice loss is isolated and contrasted to the sensitivity to low-latitude warming. In spite of some differences in experimental design, the Northern Hemisphere near-surface atmospheric sensitivity to sea-ice loss is found to be robust across models in the cold season; however, a larger inter-model spread is found at the surface in boreal summer, and in the free tropospheric circulation. In contrast, the sensitivity to low-latitude warming is most robust in the free troposphere and in the warm season, with more inter-model spread in the surface ocean and surface heat flux over the Northern Hemisphere. The robust signals associated with sea-ice loss include upward turbulent and longwave heat fluxes where sea-ice is lost, warming and freshening of the Arctic ocean, warming of the eastern North Pacific relative to the western North Pacific with upward turbulent heat fluxes in the Kuroshio extension, and salinification of the shallow shelf seas of the Arctic Ocean alongside freshening in the subpolar North Atlantic. In contrast, the robust signals associated with low-latitude warming include intensified ocean warming and upward latent heat fluxes near the western boundary currents, freshening of the Pacific Ocean, salinification of the North Atlantic, and downward sensible and longwave fluxes over the ocean.

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.

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