Attribution of late summer early autumn Arctic sea ice decline in recent decades

AbstractThe underlying mechanisms for Arctic sea ice decline can be categories as those directly related to changes in atmospheric circulations (often referred to as dynamic mechanisms) and the rest (broadly characterized as thermodynamic processes). An attribution analysis based on the self-organizing maps (SOM) method is performed to determine the relative contributions from these two types of mechanisms to the Arctic sea ice decline in August–October during 1979–2016. The daily atmospheric circulations represented by daily 500-hPa geopotential height anomalies are classified into 12 SOM patterns, which portray the spatial structures of the Arctic Oscillation and Arctic Dipole, and their transitions. Due to the counterbalance between the opposite trends among the circulation patterns, the net effect of circulation changes is small, explaining only 1.6% of the declining trend in the number of August–October sea ice days in the Arctic during 1979–2016. The majority of the trend (95.8%) is accounted for by changes in thermodynamic processes not directly related to changes in circulations, whereas for the remaining trend (2.6%) the contributions of circulation and non-circulation changes cannot be distinguished. The sea ice decline is closely associated with surface air temperature increase, which is related to increasing trends in atmospheric water vapor content, downward longwave radiation, and sea surface temperatures over the open ocean, as well as to decreasing trends in surface albedo. An analogous SOM analysis extending seasonal coverage to spring (April–October) for the same period supports the dominating role of thermodynamic forcing in decadal-scale Arctic sea ice loss.

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Recent advances in understanding the Arctic climate system state and change from a sea ice perspective: a review

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-14-10929-2014 ◽

2014 ◽

Vol 14 (7) ◽

pp. 10929-10999 ◽

Cited By ~ 3

Author(s):

R. Döscher ◽

T. Vihma ◽

E. Maksimovich

Keyword(s):

Global Warming ◽

Sea Ice ◽

Ice Cover ◽

Arctic Sea Ice ◽

Climate System ◽

Arctic Climate ◽

The Arctic ◽

Atlantic Sector ◽

Sea Ice Decline ◽

Arctic Sea

Abstract. The Arctic sea ice is the central and essential component of the Arctic climate system. The depletion and areal decline of the Arctic sea ice cover, observed since the 1970's, have accelerated after the millennium shift. While a relationship to global warming is evident and is underpinned statistically, the mechanisms connected to the sea ice reduction are to be explored in detail. Sea ice erodes both from the top and from the bottom. Atmosphere, sea ice and ocean processes interact in non-linear ways on various scales. Feedback mechanisms lead to an Arctic amplification of the global warming system. The amplification is both supported by the ice depletion and is at the same time accelerating the ice reduction. Knowledge of the mechanisms connected to the sea ice decline has grown during the 1990's and has deepened when the acceleration became clear in the early 2000's. Record summer sea ice extents in 2002, 2005, 2007 and 2012 provided additional information on the mechanisms. This article reviews recent progress in understanding of the sea ice decline. Processes are revisited from an atmospheric, ocean and sea ice perspective. There is strong evidence for decisive atmospheric changes being the major driver of sea ice change. Feedbacks due to reduced ice concentration, surface albedo and thickness allow for additional local atmosphere and ocean influences and self-supporting feedbacks. Large scale ocean influences on the Arctic Ocean hydrology and circulation are highly evident. Northward heat fluxes in the ocean are clearly impacting the ice margins, especially in the Atlantic sector of the Arctic. Only little indication exists for a direct decisive influence of the warming ocean on the overall sea ice cover, due to an isolating layer of cold and fresh water underneath the sea ice.

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Intensification of the Atlantic Water Supply to the Arctic Ocean Through Fram Strait Induced by Arctic Sea Ice Decline

Geophysical Research Letters ◽

10.1029/2019gl086682 ◽

2020 ◽

Vol 47 (3) ◽

Cited By ~ 3

Author(s):

Qiang Wang ◽

Claudia Wekerle ◽

Xuezhu Wang ◽

Sergey Danilov ◽

Nikolay Koldunov ◽

...

Keyword(s):

Sea Ice ◽

Water Supply ◽

Arctic Ocean ◽

Atlantic Water ◽

Arctic Sea Ice ◽

The Arctic ◽

Fram Strait ◽

Sea Ice Decline ◽

Arctic Sea ◽

The Arctic Ocean

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Mechanisms for low-frequency variability of summer Arctic sea ice extent

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1422296112 ◽

2015 ◽

Vol 112 (15) ◽

pp. 4570-4575 ◽

Cited By ~ 87

Author(s):

Rong Zhang

Keyword(s):

Sea Ice ◽

Heat Transport ◽

Low Frequency ◽

Arctic Sea Ice ◽

The Arctic ◽

Sea Ice Extent ◽

Low Frequency Variability ◽

Sea Ice Decline ◽

Arctic Sea ◽

Arctic Sea Ice Extent

Satellite observations reveal a substantial decline in September Arctic sea ice extent since 1979, which has played a leading role in the observed recent Arctic surface warming and has often been attributed, in large part, to the increase in greenhouse gases. However, the most rapid decline occurred during the recent global warming hiatus period. Previous studies are often focused on a single mechanism for changes and variations of summer Arctic sea ice extent, and many are based on short observational records. The key players for summer Arctic sea ice extent variability at multidecadal/centennial time scales and their contributions to the observed summer Arctic sea ice decline are not well understood. Here a multiple regression model is developed for the first time, to the author’s knowledge, to provide a framework to quantify the contributions of three key predictors (Atlantic/Pacific heat transport into the Arctic, and Arctic Dipole) to the internal low-frequency variability of Summer Arctic sea ice extent, using a 3,600-y-long control climate model simulation. The results suggest that changes in these key predictors could have contributed substantially to the observed summer Arctic sea ice decline. If the ocean heat transport into the Arctic were to weaken in the near future due to internal variability, there might be a hiatus in the decline of September Arctic sea ice. The modeling results also suggest that at multidecadal/centennial time scales, variations in the atmosphere heat transport across the Arctic Circle are forced by anticorrelated variations in the Atlantic heat transport into the Arctic.

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Arctic Sea Ice Volume Variability over 1901–2010: A Model-Based Reconstruction

Journal of Climate ◽

10.1175/jcli-d-19-0008.1 ◽

2019 ◽

Vol 32 (15) ◽

pp. 4731-4752 ◽

Cited By ~ 12

Author(s):

Axel J. Schweiger ◽

Kevin R. Wood ◽

Jinlun Zhang

Keyword(s):

Twentieth Century ◽

Sea Ice ◽

Arctic Sea Ice ◽

Ocean Modeling ◽

The Arctic ◽

Error Statistics ◽

Atlantic Sector ◽

Ice Volume ◽

Sea Ice Decline ◽

Arctic Sea

Abstract PIOMAS-20C, an Arctic sea ice reconstruction for 1901–2010, is produced by forcing the Pan-Arctic Ice Ocean Modeling and Assimilation System (PIOMAS) with ERA-20C atmospheric data. ERA-20C performance over Arctic sea ice is assessed by comparisons with measurements and data from other reanalyses. ERA-20C performs similarly with respect to the annual cycle of downwelling radiation, air temperature, and wind speed compared to reanalyses with more extensive data assimilation such as ERA-Interim and MERRA. PIOMAS-20C sea ice thickness and volume are then compared with in situ and aircraft remote sensing observations for the period of ~1950–2010. Error statistics are similar to those for PIOMAS. We compare the magnitude and patterns of sea ice variability between the first half of the twentieth century (1901–40) and the more recent period (1980–2010), both marked by sea ice decline in the Arctic. The first period contains the so-called early-twentieth-century warming (ETCW; ~1920–40) during which the Atlantic sector saw a significant decline in sea ice volume, but the Pacific sector did not. The sea ice decline over the 1979–2010 period is pan-Arctic and 6 times larger than the net decline during the 1901–40 period. Sea ice volume trends reconstructed solely from surface temperature anomalies are smaller than PIOMAS-20C, suggesting that mechanisms other than warming, such as changes in ice motion and deformation, played a significant role in determining sea ice volume trends during both periods.

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Insight: What's driving the Arctic sea ice decline?

The New Scientist ◽

10.1016/s0262-4079(08)62339-8 ◽

2008 ◽

Vol 199 (2674) ◽

pp. 9

Author(s):

Catherine Brahic

Keyword(s):

Sea Ice ◽

Arctic Sea Ice ◽

The Arctic ◽

Sea Ice Decline ◽

Arctic Sea

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Two leading modes of wintertime atmospheric circulation drive the recent warm Arctic-cold Eurasia temperature pattern

10.5194/egusphere-egu2020-9705 ◽

2020 ◽

Author(s):

kunhui Ye ◽

Gabriele Messori

Keyword(s):

Sea Ice ◽

Atmospheric Circulation ◽

North Atlantic ◽

Arctic Sea Ice ◽

The Arctic ◽

The North ◽

Downward Longwave Radiation ◽

North Asia ◽

Arctic Sea ◽

The North Atlantic

The wintertime warm Arctic-cold Eurasia (WACE) temperature trend during 1990-2010 was characterized by accelerating warming in the Arctic region, cooling in Eurasia and accelerating autumn/winter Arctic sea ice loss. We identify two atmospheric circulation modes over the North Atlantic-Northern Eurasian sector which displayed strong upward trends over the same period and can explain a large part of the observed decadal WACE pattern. Both modes bear a close resemblance to well-known teleconnection patterns and are relatively independent from anomalies in Arctic sea-ice cover. The first mode (PC1) captures the recent negative trends in the North Atlantic Oscillation and increased Greenland blocking frequency while the second mode (PC2) is reminiscent of a Rossby wave train and reflects an increased blocking frequency over the Urals and North Asia. We find that the loss in the Arctic sea ice and the upward trends in the PC1/PC2 together account for most of the decadal Arctic warming trend (>80%). However, the decadal Eurasian cooling trends may be primarily ascribed to the two circulation modes alone: all of the cooling in Siberia is contributed to by the PC1, and 65% of the cooling in East Asia by their combination (the contribution by PC2 doubles that by PC1). Enhanced intraseasonal activity of the two circulation modes increases blocking frequencies over Greenland, the Ural region and North Asia, which drive anomalous moisture/heat flux towards the Arctic and alter the downward longwave radiation. It weakens warm advection and enhances advection of Arctic cold airmass towards Eurasia.

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Suppression of Arctic sea ice growth by winter clouds and snowfall

10.21203/rs.3.rs-84779/v1 ◽

2021 ◽

Author(s):

Won-il Lim ◽

Hyo-Seok Park ◽

Andrew Stewart ◽

Kyong-Hwan Seo

Keyword(s):

Sea Ice ◽

Longwave Radiation ◽

Arctic Sea Ice ◽

The Arctic ◽

Ice Thickness ◽

Sea Ice Thickness ◽

Ice Growth ◽

Downward Longwave Radiation ◽

Arctic Sea ◽

The Impact

Abstract The ongoing Arctic warming has been pronounced in winter and has been associated with an increase in downward longwave radiation. While previous studies have demonstrated that poleward moisture flux into the Arctic strengthens downward longwave radiation, less attention has been given to the impact of the accompanying increase in snowfall. Here, utilizing state-of-the art sea ice models, we show that typical winter snowfall anomalies of 1.0 cm, accompanied by positive downward longwave radiation anomalies of ~5 W m-2 can decrease sea ice thickness by around 5 cm in the following spring over the Eurasian Seas. This basin-wide ice thinning is followed by a shrinking of summer ice extent in extreme cases. In the winter of 2016–17, anomalously strong warm/moist air transport combined with ~2.5 cm increase in snowfall decreased spring ice thickness by ~10 cm and decreased the following summer sea ice extent by 5–30%. Projected future reductions in the thickness of Arctic sea ice and snow will amplify the impact of anomalous winter snowfall events on winter sea ice growth and seasonal sea ice thickness.

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Two Leading Modes of Wintertime Atmospheric Circulation Drive the Recent Warm Arctic–Cold Eurasia Temperature Pattern

Journal of Climate ◽

10.1175/jcli-d-19-0403.1 ◽

2020 ◽

Vol 33 (13) ◽

pp. 5565-5587 ◽

Cited By ~ 1

Author(s):

Kunhui Ye ◽

Gabriele Messori

Keyword(s):

Sea Ice ◽

Atmospheric Circulation ◽

North Atlantic ◽

Arctic Sea Ice ◽

The Arctic ◽

The North ◽

Downward Longwave Radiation ◽

North Asia ◽

Arctic Sea ◽

The North Atlantic

AbstractThe wintertime warm Arctic–cold Eurasia (WACE) temperature trend during 1990–2010 was characterized by accelerating warming in the Arctic region, cooling in Eurasia, and accelerating autumn/winter Arctic sea ice loss. We identify two atmospheric circulation modes over the North Atlantic–northern Eurasian sector that displayed strong upward trends over the same period and can explain a large part of the observed decadal WACE pattern. Both modes bear a close resemblance to well-known teleconnection patterns and are relatively independent from variability in Arctic sea ice cover. The first mode (PC1) captures the recent negative trends in the North Atlantic Oscillation and increased Greenland blocking frequency, while the second mode (PC2) is reminiscent of a Rossby wave train and reflects an increased blocking frequency over the Urals and north Asia. We find that the loss in the Arctic sea ice and the upward trends in PC1 and PC2 together account for most of the decadal Arctic warming trend (>80%). However, the decadal Eurasian cooling trends may be primarily ascribed to the two circulation modes alone: all of the cooling in Siberia is contributed to by PC1 and 65% of the cooling in East Asia by their combination (the contribution by PC2 doubles that by PC1). Enhanced intraseasonal activity of the two circulation modes increases blocking frequencies over Greenland, the Ural region, and north Asia, which drive anomalous moisture/heat flux toward the Arctic and alter the downward longwave radiation. This also weakens warm advection and enhances advection of cold Arctic airmasses towards Eurasia.

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Voices of the Sea Ice: engaging an Arctic community to communicate impacts of climate change

10.5194/egusphere-egu2020-12661 ◽

2020 ◽

Author(s):

David Lipson ◽

Kim Reasor ◽

Kååre Sikuaq Erickson

Keyword(s):

Climate Change ◽

Sea Ice ◽

Ice Cover ◽

Arctic Sea Ice ◽

The Arctic ◽

Digital Version ◽

Sea Ice Decline ◽

Arctic Sea ◽

The World ◽

Impacts Of Climate Change

The predominantly Inupiat people of Utqia&#289;vik, Alaska are among those who will be most impacted by climate change and the loss of Arctic sea ice in the near future. Subsistence hunting of marine mammals associated with sea ice is central to the Inupiat way of life. Furthermore, their coastal homes and infrastructure are increasingly subject to damage from increased wave action on ice-free Beaufort and Chukchi Seas. While the people of this region are among the most directly vulnerable to climate change, the subject is not often discussed in the elementary school curriculum. Meanwhile, in many other parts of the world, the impacts of climate change are viewed as abstract and remote. We worked with fifth grade children in Utqia&#289;vik both to educate them, but also to engage them in helping us communicate to rest of the world, in an emotionally resonant way, the direct impacts of climate change on families in this Arctic region. The team consisted of a scientist (Lipson), an artist (Reasor) and an outreach specialist (Erickson) of Inupiat heritage from a village in Alaska. We worked with four 5th grade classes of about 25 students each at Fred Ipalook Elementary in Utqia&#289;vik, AK. The scientist gave a short lecture about sea ice and climate change in the Arctic, with emphasis on local impacts to hunting and infrastructure (with interjections from the local outreach specialist). We then showed the students a large poster of historical and projected sea ice decline, and asked the students to help us fill in the white space beneath the lines. The artist led the children in making small art pieces that represent things that are important to their lives in Utqia&#289;vik (they were encouraged to paint animals, but they were free to do whatever they wanted). We returned to the class later that week and had each student briefly introduce themselves and their painting, and place it to the large graph of sea ice decline, which included the dire predictions of the RCP8.5 scenario. At the end we added the more hopeful RCP2.6 scenario to end on a positive note. The artist then painted in the more hopeful green line by hand. The result was a poster showing historical and projected Arctic sea ice cover, with 100 beautiful paintings by children of things that are dear to them about their home being squeezed into a smaller region as the sea ice cover diminishes. We scanned all the artwork to make a digital version of the poster, and left the original with the school. These materials are being converted into an interactive webpage where viewers can click on the individual painting for detail, and get selected recordings of the children&#8217;s statements about their artwork. This project can serve as a nucleus for communicating to other classes and adults about the real impacts of climate change in people&#8217;s lives.

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Revisiting the Linkages between the Variability of Atmospheric Circulations and Arctic Melt-Season Sea Ice Cover at Multiple Time Scales

10.5194/egusphere-egu2020-373 ◽

2020 ◽

Author(s):

Lejiang Yu ◽

Sharon Zhong

Keyword(s):

Sea Ice ◽

Arctic Ocean ◽

Time Scales ◽

Arctic Sea Ice ◽

The Arctic ◽

Multiple Time Scales ◽

Multiple Time ◽

Atmospheric Circulations ◽

The Pacific ◽

Arctic Sea

The sharp decline of Arctic sea ice in recent decades has captured the attention of the climate science community. A majority of climate analyses performed to date have used monthly or seasonal data. Here, however, we analyze daily sea ice data for 1979&#8211;2016 using the self-organizing map (SOM) method to further examine and quantify the contributions of atmospheric circulation changes to the melt-season Arctic sea ice variability. Our results reveal two main variability modes: the Pacific sector mode and the Barents and Kara Seas mode, which together explain about two-thirds of the melt-season Arctic sea ice variability and more than 40% of its trend for the study period. The change in the frequencies of the two modes appears to be associated with the phase shift of the Pacific decadal oscillation (PDO) and the Atlantic multidecadal oscillation (AMO). The PDO and AMO trigger anomalous atmospheric circulations, in particular, the Greenland high and the North Atlantic Oscillation and anomalous warm and cold air advections into the Arctic Ocean. The changes in surface air temperature, lower-atmosphere moisture, and downwelling longwave radiation associated with the advection are consistent with the melt-season sea ice anomalies observed in various regions of the Arctic Ocean. These results help better understand the predictability of Arctic sea ice on multiple (synoptic, intraseasonal, and interannual) time scales.

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