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.

Response/feedback of the Arctic Ocean in the Northern Hemisphere climate system: the sea-level joker

2020 ◽  
Author(s):  
Claude Hillaire-Marcel ◽  
Anne de Vernal ◽  
Yanguang Liu
Keyword(s):  
Sea Ice ◽  
Arctic Ocean ◽  
Northern Hemisphere ◽  
North Atlantic ◽  
Climate System ◽  
The Arctic ◽  
Bering Strait ◽  
The North ◽  
The Arctic Ocean ◽  
The Status

<p>The Arctic Ocean is a major player in the climate system of the Northern Hemisphere due to its role vs albedo, atmospheric pressure regimes, and thermohaline circulation. It shows large amplitude variability from millennial, to decadal and seasonal time scales. At millennial time scales, two drastically distinct regimes prevail primarily in relation with ocean volume and sea level (SL) changes: A modern like system, with a high SL when the Arctic Ocean shelves are submerged and Bering Strait is opened vs a glacial one, with a low SL, when shelves are emerged and partly glaciated and Bering Strait is closed. In the modern system, large submerged shelves result in high productivity, high sea-ice production rates and sea ice-rafting deposition in the Central Arctic. Moreover, a fully open Bering Strait, with SL at the present elevation, contributes about 40% of the freshwater budget of the Arctic Ocean (Woodgate & Aagaard, 2005, doi:10.1029/2004GL021747), and supports Si fluxes of about 20 kmol.s<sup>-1</sup> towards the Western Arctic (Torres-Valdés et al., 2013, doi:10.1002/jgrc.20063), thus impacting primary productivity. Under low SL conditions, the Arctic Ocean is linked exclusively to the North Atlantic, through practically a single gateway, that of Fram Strait. Sedimentation in the Central Arctic is then dominated ice-rafting deposition from icebergs, thus controlled by streaming and calving processes along surrounding ice sheets. Due to its shallowness (< 50 m), the Bering Strait gateway becomes effective at a very late stage of glacial to interglacial transitions but closes early during reverse climate trends. Sedimentary records from shelves North of Strait may provide information on the status of the gateway, so far, for the present interglacial. Clay minerals in cores from the northern Alaskan shelf (Ortiz et al., 2009, doi:10.1016/j.gloplacha.2009.03.020) and micropaleontological tracers from the Chukchi Sea southern shelf (present study) can be used to document the status of the gateway. Here, North Pacific microfossils transported by currents through the gateway demonstrate its full effectiveness at ca 6 ka BP, well after the insolation maximum of the early Holocene but when SL had reached its maximum postglacial elevation, with significant impacts on Arctic Ocean salinity, sea-ice cover and productivity.. This out-of-phase behavior of the Arctic Ocean may have impacted the North Atlantic and Northern Hemisphere climate system, as the openings and closings of Bering Strait constitute critical tipping points on this system, off out of phase with other parameters controlling more globally the climate of the Northern Hemisphere.</p>

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.

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

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

<p>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.  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. 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. 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’s Global Deterministic Prediction System Reforecasts.</p><p>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. </p>

The shallowing surface temperature inversions in the Arctic

2021 ◽  
pp. 1-30
Author(s):  
Lin Zhang ◽  
Minghu Ding ◽  
Tingfeng Dou ◽  
Yi Huang ◽  
Junmei Lv ◽  
...  
Keyword(s):  
Sea Ice ◽  
Arctic Ocean ◽  
21St Century ◽  
Barents Sea ◽  
Atmospheric Stability ◽  
Heat Fluxes ◽  
Spatiotemporal Variability ◽  
The Arctic ◽  
The Arctic Ocean ◽  
Temperature Inversions

AbstractTemperature inversion plays an important role in various physical processes by affecting the atmospheric stability, regulating the development of clouds and fog, and controlling the transport of heat and moisture fluxes. In the past few decades, previous studies have analyzed the spatiotemporal variability of Arctic inversions, but few studies have investigated changes in temperature inversions. In this study, the changes in the depth of Arctic inversions in the mid-21st century are projected based on a 30-member ensemble from the Community Earth System Model Large Ensemble (CESM-LE) project. The ERA-Interim, JRA-55, and NCEP-NCAR reanalyses were employed to verify the model results. The CESM-LE can adequately reproduce the spatial distribution and trends of present-day inversion depth in the Arctic, and the simulation is better in winter. The mean inversion depth in the CESM-LE is slightly underestimated, and the discrepancy is less than 11 hPa within a reasonable range. The model results show that during the mid-21st century, the inversion depth will strongly decrease in autumn and slightly decrease in winter. The shallowing of inversion is most obvious over the Arctic Ocean, and the maximum decrease is over 65 hPa in the Pacific sector in autumn. In contrast, the largest decrease in the inversion depth, which is more than 45 hPa, occurs over the Barents Sea in winter. Moreover, the area where the inversion shallows is consistent with the area where the sea ice is retreating, indicating that the inversion depth over the Arctic Ocean in autumn and winter is likely regulated by the sea ice extent through modulating surface heat fluxes.

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 Impact of Poleward Moisture Transport from the North Pacific on the Acceleration of Sea Ice Loss in the Arctic since 2002

2017 ◽  
Vol 30 (17) ◽  
pp. 6757-6769 ◽  
Author(s):  
H. J. Lee ◽  
M. O. Kwon ◽  
S.-W. Yeh ◽  
Y.-O. Kwon ◽  
W. Park ◽  
...  
Keyword(s):  
Sea Ice ◽  
Arctic Ocean ◽  
North Pacific ◽  
Moisture Transport ◽  
Arctic Sea Ice ◽  
Specific Humidity ◽  
The Arctic ◽  
The North ◽  
The Arctic Ocean ◽  
The North Pacific

Abstract Arctic sea ice area (SIA) during late summer and early fall decreased substantially over the last four decades, and its decline accelerated beginning in the early 2000s. Statistical analyses of observations show that enhanced poleward moisture transport from the North Pacific to the Arctic Ocean contributed to the accelerated SIA decrease during the most recent period. As a consequence, specific humidity in the Arctic Pacific sector significantly increased along with an increase of downward longwave radiation beginning in 2002, which led to a significant acceleration in the decline of SIA in the Arctic Pacific sector. The resulting sea ice loss led to increased evaporation in the Arctic Ocean, resulting in a further increase of the specific humidity in mid-to-late fall, thus acting as a positive feedback to the sea ice loss. The overall set of processes is also found in a long control simulation of a coupled climate model.

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 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.

scholarly journals The Influence of Sea Ice on Ocean Heat Uptake in Response to Increasing CO2

2006 ◽  
Vol 19 (11) ◽  
pp. 2437-2450 ◽  
Author(s):  
C. M. Bitz ◽  
P. R. Gent ◽  
R. A. Woodgate ◽  
M. M. Holland ◽  
R. Lindsay
Keyword(s):  
Southern Ocean ◽  
Sea Ice ◽  
Arctic Ocean ◽  
North Atlantic ◽  
Deep Ocean ◽  
Temperature Gradients ◽  
The Arctic ◽  
Ocean Heat Uptake ◽  
Heat Uptake ◽  
The Arctic Ocean

Abstract Two significant changes in ocean heat uptake that occur in the vicinity of sea ice cover in response to increasing CO2 are investigated with Community Climate System Model version 3 (CCSM3): a deep warming below ∼500 m and extending down several kilometers in the Southern Ocean and warming in a ∼200-m layer just below the surface in the Arctic Ocean. Ocean heat uptake caused by sea ice retreat is isolated by running the model with the sea ice albedo reduced artificially alone. This integration has a climate response with strong ocean heat uptake in the Southern Ocean and modest ocean heat uptake in the subsurface Arctic Ocean. The Arctic Ocean warming results from enhanced ocean heat transport from the northern North Atlantic. At the time of CO2 doubling, about 1/3 of the heat transport anomaly results from advection of anomalously warm water and 2/3 results from strengthened inflow. At the same time the overturning circulation is strengthened in the northern North Atlantic and Arctic Oceans. Wind stress changes cannot explain the circulation changes, which instead appear related to strengthened convection along the Siberian shelves. Deep ocean warming in the Southern Ocean is initiated by weakened convection, which is mainly a result of surface freshening through altered sea ice and ocean freshwater transport. Below about 500 m, changes in convection reduce the vertical and meridional temperature gradients in the Southern Ocean, which significantly reduce isopycnal diffusion of heat upward around Antarctica. The geometry of the sea ice cover and its influence on convection have a strong influence on ocean temperature gradients, making sea ice an important player in deep ocean heat uptake in the Southern Ocean.

Sign in / Sign up

Export Citation Format

Share Document