scholarly journals Comparison of Mechanisms for Low-Frequency Variability of Summer Arctic Sea Ice in Three Coupled Models

2018 ◽  
Vol 31 (3) ◽  
pp. 1205-1226 ◽  
Author(s):  
Dawei Li ◽  
Rong Zhang ◽  
Thomas Knutson
Keyword(s):  
Sea Ice ◽  
Heat Transport ◽  
Low Frequency ◽  
Arctic Sea Ice ◽  
The Arctic ◽  
Coupled Models ◽  
Surface Warming ◽  
Low Frequency Variability ◽  
Sea Ice Decline ◽  
Arctic Sea

Abstract In this study the mechanisms for low-frequency variability of summer Arctic sea ice are analyzed using long control simulations from three coupled models (GFDL CM2.1, GFDL CM3, and NCAR CESM). Despite different Arctic sea ice mean states, there are many robust features in the response of low-frequency summer Arctic sea ice variability to the three key predictors (Atlantic and Pacific oceanic heat transport into the Arctic and the Arctic dipole) across all three models. In all three models, an enhanced Atlantic (Pacific) heat transport into the Arctic induces summer Arctic sea ice decline and surface warming, especially over the Atlantic (Pacific) sector of the Arctic. A positive phase of the Arctic dipole induces summer Arctic sea ice decline and surface warming on the Pacific side, and opposite changes on the Atlantic side. There is robust Bjerknes compensation at low frequency, so the northward atmospheric heat transport provides a negative feedback to summer Arctic sea ice variations. The influence of the Arctic dipole on summer Arctic sea ice extent is more (less) effective in simulations with less (excessive) climatological summer sea ice in the Atlantic sector. The response of Arctic sea ice thickness to the three key predictors is stronger in models that have thicker climatological Arctic sea ice.

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

2015 ◽  
Vol 112 (15) ◽  
pp. 4570-4575 ◽  
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.

scholarly journals Dynamical and Thermodynamical Impacts of High- and Low-Frequency Atmospheric Eddies on the Initial Melt of Arctic Sea Ice

2017 ◽  
Vol 30 (3) ◽  
pp. 865-883 ◽  
Author(s):  
Bradley M. Hegyi ◽  
Yi Deng
Keyword(s):  
Sea Ice ◽  
Heat Transport ◽  
High Frequency ◽  
Low Frequency ◽  
Longwave Radiation ◽  
Arctic Sea Ice ◽  
The Arctic ◽  
Positive Anomaly ◽  
Meridional Heat Transport ◽  
Arctic Sea

Abstract The role of high-frequency and low-frequency eddies in the melt onset of Arctic sea ice is investigated through an examination of eddy effects on lower-tropospheric (1000–500 hPa) meridional heat transport into the Arctic and local surface downwelling shortwave and longwave radiation. Total and eddy components of the meridional heat transport into the Arctic from 1979 to 2012 are calculated from reanalysis data, and surface radiation data are acquired from the NASA Clouds and the Earth’s Radiant Energy System (CERES) project dataset. There is a significant positive correlation between the mean initial melt date and the September sea ice minimum extent, with each quantity characterized by a negative trend. Spatially, the earlier mean melt onset date is primarily found in a region bounded by 90°E and 130°W. The decline in this region is steplike and not associated with an increase in meridional heat transport but with an earlier appearance of above-freezing temperatures in the troposphere. In most years, discrete short-duration episodes of melt onset over a large area occur. In an investigation of two of these melt episodes, a positive total meridional heat transport is associated with the peak melt, with the product of high-frequency eddy wind and mean temperature fields being the most important contributor. Additionally, there is a key positive anomaly in surface downwelling longwave radiation immediately preceding the peak melt that is associated with increased cloud cover and precipitable water. These results suggest the importance of carefully considering and properly representing atmospheric eddies when modeling the melt onset of Arctic sea ice.

scholarly journals Low-frequency bursts of horizontally polarized waves in the Arctic sea-ice cover

2011 ◽  
Vol 57 (202) ◽  
pp. 231-237 ◽  
Author(s):  
David Marsan ◽  
Jérôme Weiss ◽  
Jean-Philippe Métaxian ◽  
Jacques Grangeon ◽  
Pierre-François Roux ◽  
...  
Keyword(s):  
Sea Ice ◽  
Regional Scale ◽  
Low Frequency ◽  
Ice Cover ◽  
Arctic Sea Ice ◽  
The Arctic ◽  
Strong Activity ◽  
Temporal Sampling ◽  
Polarized Waves ◽  
Arctic Sea

AbstractWe report the detection of bursts of low-frequency waves, typically f = 0.025 Hz, on horizontal channels of broadband seismometers deployed on the Arctic sea-ice cover during the DAMOCLES (Developing Arctic Modeling and Observing Capabilities for Long-term Environmental Studies) experiment in spring 2007. These bursts have amplitudes well above the ambient ice swell and a lower frequency content. Their typical duration is of the order of minutes. They occur at irregular times, with periods of relative quietness alternating with periods of strong activity. A significant correlation between the rate of burst occurrences and the ice-cover deformation at the ∼400 km scale centered on the seismic network suggests that these bursts are caused by remote, episodic deformation involving shearing across regional-scale leads. This observation opens the possibility of complementing satellite measurements of ice-cover deformation, by providing a much more precise temporal sampling, hence a better characterization of the processes involved during these deformation events.

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

2014 ◽  
Vol 14 (7) ◽  
pp. 10929-10999 ◽  
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.

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

2020 ◽  
Vol 47 (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

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

2019 ◽  
Vol 32 (15) ◽  
pp. 4731-4752 ◽  
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.

scholarly journals Model resolution influence on simulated sea ice decline

2008 ◽  
Vol 2 (5) ◽  
pp. 759-776 ◽  
Author(s):  
J. O. Sewall
Keyword(s):  
Sea Ice ◽  
Heat Transport ◽  
Coupled Model ◽  
Ocean Model ◽  
Arctic Sea Ice ◽  
Model Resolution ◽  
Ocean Heat Transport ◽  
Sea Ice Decline ◽  
Arctic Sea ◽  
Model Predictions

Abstract. Satellite observations and model predictions of recent and future Arctic sea ice decline have raised concerns over the timing and potential impacts of a seasonally ice-free Arctic Ocean. Model predictions of seasonally ice-free Arctic conditions are, however, highly variable. Here I present results from fourteen climate system models from the World Climate Research Programme's (WCRP's) Coupled Model Intercomparison Project phase 3 (CMIP3) multi-model dataset that indicate modeled Arctic sea ice sensitivity to increased atmospheric CO2 forcing is strongly correlated with ice/ocean model horizontal resolution. Based on coupled model analyses and ice only simulations with the Los Alamos National Lab sea ice model (CICE), the correlation between declining Arctic sea ice cover and ice/ocean model resolution appears to depend largely on ocean model resolution and its influence on ocean heat transport into the Arctic basin. The correlation between model resolution, northward ocean heat transport, and the degree of Arctic ice loss is independent of ice model physics and complexity. This not only illustrates one difficulty in using numerical models to accurately predict the timing and magnitude of Arctic sea ice decline under increasing atmospheric greenhouse gas forcing, but also highlights one area where improved simulation (of northward ocean heat transport) could greatly decrease the uncertainties associated with predictions of future Arctic sea ice cover.

Atmospheric and oceanic drivers of regional Arctic winter sea-ice variability in present and future climates

2021 ◽  
Author(s):  
Jakob Dörr ◽  
Marius Årthun ◽  
Tor Eldevik ◽  
Erica Madonna
Keyword(s):  
Sea Ice ◽  
Arctic Ocean ◽  
Heat Transport ◽  
Barents Sea ◽  
Arctic Sea Ice ◽  
The Arctic ◽  
Ocean Heat Transport ◽  
The Pacific ◽  
Arctic Sea ◽  
The Arctic Ocean

<p>The recent retreat of Arctic sea ice area is overlaid by strong internal variability on all timescales. In winter, sea ice retreat and variability are currently dominated by the Barents Sea, primarily driven by variable ocean heat transport from the Atlantic. Climate models from the latest intercomparison project CMIP6 project that the future loss of winter Arctic sea ice spreads throughout the Arctic Ocean and, hence, that other regions of the Arctic Ocean will see increased sea-ice variability. It is, however, not known how the influence of ocean heat transport will change, and to what extent and in which regions other drivers, such as atmospheric circulation or river runoff into the Arctic Ocean, will become important. Using a combination of observations and simulations from the Community Earth System Model Large Ensemble (CESM-LE), we analyze and contrast the present and future regional drivers of the variability of the winter Arctic sea ice cover. We find that for the recent past, both observations and CESM-LE show that sea ice variability in the Atlantic and Pacific sector of the Arctic Ocean is influenced by ocean heat transport through the Barents Sea and Bering Strait, respectively. The two dominant modes of large-scale atmospheric variability – the Arctic Oscillation and the Pacific North American pattern – are only weakly related to recent regional sea ice variability. However, atmospheric circulation anomalies associated with regional sea ice variability show distinct patterns for the Atlantic and Pacific sectors consistent with heat and humidity transport from lower latitudes. In the future, under a high emission scenario, CESM-LE projects a gradual expansion of the footprint of the Pacific and Atlantic inflows, covering the whole Arctic Ocean by 2050-2079. This study highlights the combined importance of future Atlantification and Pacification of the Arctic Ocean and improves our understanding of internal climate variability which essential in order to predict future sea ice changes under anthropogenic warming.   </p><p> </p>

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

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

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

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