Respective roles of direct GHG radiative forcing and induced Arctic sea ice loss on the Northern Hemisphere atmospheric circulation

Abstract Internal variability in twenty-first-century summer Arctic sea ice loss and its relationship to the large-scale atmospheric circulation is investigated in a 39-member Community Climate System Model, version 3 (CCSM3) ensemble for the period 2000–61. Each member is subject to an identical greenhouse gas emissions scenario and differs only in the atmospheric model component's initial condition. September Arctic sea ice extent trends during 2020–59 range from −2.0 × 106 to −5.7 × 106 km2 across the 39 ensemble members, indicating a substantial role for internal variability in future Arctic sea ice loss projections. A similar nearly threefold range (from −7.0 × 103 to −19 × 103 km3) is found for summer sea ice volume trends. Higher rates of summer Arctic sea ice loss in CCSM3 are associated with enhanced transpolar drift and Fram Strait ice export driven by surface wind and sea level pressure patterns. Over the Arctic, the covarying atmospheric circulation patterns resemble the so-called Arctic dipole, with maximum amplitude between April and July. Outside the Arctic, an atmospheric Rossby wave train over the Pacific sector is associated with internal ice loss variability. Interannual covariability patterns between sea ice and atmospheric circulation are similar to those based on trends, suggesting that similar processes govern internal variability over a broad range of time scales. Interannual patterns of CCSM3 ice–atmosphere covariability compare well with those in nature and in the newer CCSM4 version of the model, lending confidence to the results. Atmospheric teleconnection patterns in CCSM3 suggest that the tropical Pacific modulates Arctic sea ice variability via the aforementioned Rossby wave train. Large ensembles with other coupled models are needed to corroborate these CCSM3-based findings.

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The Role of Extratropical Ocean Warming in the Coupled Climate Response to Arctic Sea Ice Loss

Journal of Climate ◽

10.1175/jcli-d-18-0192.1 ◽

2018 ◽

Vol 31 (22) ◽

pp. 9193-9206 ◽

Cited By ~ 6

Author(s):

Russell Blackport ◽

Paul J. Kushner

Keyword(s):

Sea Ice ◽

Atmospheric Circulation ◽

General Circulation ◽

Arctic Sea Ice ◽

Ocean Warming ◽

The Arctic ◽

Climate Response ◽

Arctic Sea ◽

Arctic Sea Ice Loss

The role of extratropical ocean warming in the coupled climate response to Arctic sea ice loss is investigated using coupled atmosphere–ocean general circulation model (AOGCM) and uncoupled atmospheric-only (AGCM) experiments. Coupled AOGCM experiments driven by sea ice albedo reduction and greenhouse gas–dominated radiative forcing are used to diagnose the extratropical sea surface temperature (SST) response to sea ice loss. Sea ice loss is then imposed in AGCM experiments both with and without these extratropical SST changes, which are found to extend beyond the regions where sea ice is lost. Sea ice loss in isolation drives warming that is confined to the Arctic lower troposphere and only a weak atmospheric circulation response. When the extratropical SST response caused by sea ice loss is also included in the forcing, the warming extends into the Arctic midtroposphere during winter. This coincides with a stronger atmospheric circulation response, including an equatorward shift in the eddy-driven jet, a deepening of the Aleutian low, and an expansion of the Siberian high. Similar results are found whether the extratropical SST forcing is taken directly from the AOGCM driven by sea ice loss, or whether they are diagnosed using a two-parameter pattern scaling technique where tropical adjustment to sea ice loss is removed. These results suggest that AGCM experiments that are driven by sea ice loss and only local SST increases will underestimate the Arctic midtroposphere warming and atmospheric circulation response to sea ice loss, compared to AOGCM simulations and the real world.

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Observed forcing-feedback processes between Northern Hemisphere atmospheric circulation and Arctic sea ice coverage

Journal of Geophysical Research Atmospheres ◽

10.1029/2009jd013574 ◽

2010 ◽

Vol 115 (D14) ◽

Cited By ~ 61

Author(s):

Qigang Wu ◽

Xiangdong Zhang

Keyword(s):

Sea Ice ◽

Atmospheric Circulation ◽

Northern Hemisphere ◽

Arctic Sea Ice ◽

Ice Coverage ◽

Arctic Sea

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Recent summer Arctic atmospheric circulation anomalies in a historical perspective

The Cryosphere Discussions ◽

10.5194/tcd-8-4823-2014 ◽

2014 ◽

Vol 8 (5) ◽

pp. 4823-4847 ◽

Cited By ~ 1

Author(s):

A. Belleflamme ◽

X. Fettweis ◽

M. Erpicum

Keyword(s):

Sea Ice ◽

Atmospheric Circulation ◽

Greenland Ice Sheet ◽

Arctic Region ◽

Arctic Sea Ice ◽

The Arctic ◽

Arctic Sea ◽

Circulation Anomalies ◽

Arctic Sea Ice Loss ◽

The Arctic Region

Abstract. A significant increase in the summertime occurrence of a high pressure area over the Beaufort Sea and Greenland has been observed from the beginning of the 2000's, and particularly between 2007 and 2012. These circulation anomalies are likely partly responsible for the enhanced Greenland ice sheet melt as well as the Arctic sea ice loss observed since 2007. Therefore, it is interesting to analyse whether similar conditions might have happened since the late 19th century over the Arctic region. We have used an atmospheric circulation type classification based on daily mean sea level pressure and 500 hPa geopotential height data from four reanalysis datasets (ERA-Interim, ERA-40, NCEP/NCAR, and 20CRv2) to put the recent circulation anomalies in perspective with the atmospheric circulation variability since 1871. We found that circulation conditions similar to 2007–2012 have occurred in the past, despite a higher uncertainty of the reconstructed circulation before 1940. But the recent anomalies largely exceed the interannual variability of the atmospheric circulation of the Arctic region. These circulation anomalies are linked with the North Atlantic Oscillation suggesting that they are not limited to the Arctic. Finally, they favour summertime Arctic sea ice loss.

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Multimodel Evidence for an Atmospheric Circulation Response to Arctic Sea Ice Loss in the CMIP5 Future Projections

Geophysical Research Letters ◽

10.1002/2017gl076096 ◽

2018 ◽

Vol 45 (2) ◽

pp. 1011-1019 ◽

Cited By ~ 26

Author(s):

G. Zappa ◽

F. Pithan ◽

T. G. Shepherd

Keyword(s):

Sea Ice ◽

Atmospheric Circulation ◽

Arctic Sea Ice ◽

Future Projections ◽

Arctic Sea ◽

Arctic Sea Ice Loss

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A Cold Event in Asia during January–February 2012 and Its Possible Association with Arctic Sea Ice Loss

Journal of Climate ◽

10.1175/jcli-d-16-0115.1 ◽

2017 ◽

Vol 30 (19) ◽

pp. 7971-7990 ◽

Cited By ~ 11

Author(s):

Bingyi Wu ◽

Kun Yang ◽

Jennifer A. Francis

Keyword(s):

Sea Ice ◽

Atmospheric Circulation ◽

Arctic Sea Ice ◽

Simulation Experiments ◽

Cold Event ◽

Central Eurasia ◽

Arctic Sea ◽

Northeastern Pacific ◽

Cold Events ◽

Arctic Sea Ice Loss

Abstract Through both observational analyses and simulation experiments, this study investigates the intraseasonal evolution of atmospheric circulation anomalies associated with a persistent cold event in the Asian continent during late January–early February 2012, and the possible association with Arctic sea ice loss and Arctic atmospheric circulation during the preceding summer. The results suggest that the northeastern Pacific–Aleutian region and central Eurasia are two critical areas where the atmospheric circulation evolution contributed to the development of this cold event. A persistent increase in sea level pressure (SLP) over the Aleutian region was a predominant feature prior to the cold event, and then decreasing SLP over this region was concurrent with both occurrence of a polar blocking high aloft and rapid strengthening of the Siberian high, triggering outbreaks of Arctic air over the Asian continent. Consequently, the influence of the Aleutian region on this cold event (i.e., the downstream effect of the atmospheric circulation) played a critical role. Simulation experiments demonstrate that Arctic atmospheric circulation conditions in the summer of 2011 significantly enhanced a negative feedback of Arctic sea ice loss on atmospheric circulation over the Aleutian region and central Eurasia during the ensuing wintertime, which could have led to the favorable atmospheric circulation that facilitated the occurrence of cold events resembling the one in 2012. This study also implies that the Aleutian low and disturbances in the midlatitudes over the northeastern Pacific may provide precursors that could increase skill in predicting the intraseasonal evolution of extreme cold events over Eurasia.

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Response of the Wintertime Northern Hemisphere Atmospheric Circulation to Current and Projected Arctic Sea Ice Decline: A Numerical Study with CAM5

Journal of Climate ◽

10.1175/jcli-d-13-00272.1 ◽

2014 ◽

Vol 27 (1) ◽

pp. 244-264 ◽

Cited By ~ 157

Author(s):

Yannick Peings ◽

Gudrun Magnusdottir

Keyword(s):

Sea Ice ◽

Atmospheric Circulation ◽

Northern Hemisphere ◽

Numerical Study ◽

Arctic Sea Ice ◽

The Arctic ◽

Late Winter ◽

Stratospheric Polar Vortex ◽

Sea Ice Decline ◽

Arctic Sea

Abstract The wintertime Northern Hemisphere (NH) atmospheric circulation response to current (2007–12) and projected (2080–99) Arctic sea ice decline is examined with the latest version of the Community Atmospheric Model (CAM5). The numerical experiments suggest that the current sea ice conditions force a remote atmospheric response in late winter that favors cold land surface temperatures over midlatitudes, as has been observed in recent years. Anomalous Rossby waves forced by the sea ice anomalies penetrate into the stratosphere in February and weaken the stratospheric polar vortex, resulting in negative anomalies of the northern annular mode (NAM) that propagate downward during the following weeks, especially over the North Pacific. The seasonality of the response is attributed to timing of the phasing between the forced and climatological waves. When sea ice concentration taken from projections of conditions at the end of the twenty-first century is prescribed to the model, negative anomalies of the NAM are visible in the troposphere, both in early and late winter. This response is mainly driven by the large warming of the lower troposphere over the Arctic, as little impact is found in the stratosphere in this experiment. As a result of the thermal expansion of the polar troposphere, the westerly flow is decelerated and a weak but statistically significant increase of the midlatitude meanders is identified. However, the thermodynamical response extends beyond the Arctic and offsets the dynamical effect, such that the stronger sea ice forcing has limited impact on the intensity of cold extremes over midlatitudes.

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