Articles | Volume 9, issue 2
https://doi.org/10.5194/os-9-217-2013
© Author(s) 2013. This work is distributed under
the Creative Commons Attribution 3.0 License.
the Creative Commons Attribution 3.0 License.
https://doi.org/10.5194/os-9-217-2013
© Author(s) 2013. This work is distributed under
the Creative Commons Attribution 3.0 License.
the Creative Commons Attribution 3.0 License.
Arctic rapid sea ice loss events in regional coupled climate scenario experiments
R. Döscher
SMHI/Rossby Centre Folkborgsvägen 17, 60176 Norrköping, Sweden
T. Koenigk
SMHI/Rossby Centre Folkborgsvägen 17, 60176 Norrköping, Sweden
Related authors
Ralf Döscher, Mario Acosta, Andrea Alessandri, Peter Anthoni, Thomas Arsouze, Tommi Bergman, Raffaele Bernardello, Souhail Boussetta, Louis-Philippe Caron, Glenn Carver, Miguel Castrillo, Franco Catalano, Ivana Cvijanovic, Paolo Davini, Evelien Dekker, Francisco J. Doblas-Reyes, David Docquier, Pablo Echevarria, Uwe Fladrich, Ramon Fuentes-Franco, Matthias Gröger, Jost v. Hardenberg, Jenny Hieronymus, M. Pasha Karami, Jukka-Pekka Keskinen, Torben Koenigk, Risto Makkonen, François Massonnet, Martin Ménégoz, Paul A. Miller, Eduardo Moreno-Chamarro, Lars Nieradzik, Twan van Noije, Paul Nolan, Declan O'Donnell, Pirkka Ollinaho, Gijs van den Oord, Pablo Ortega, Oriol Tintó Prims, Arthur Ramos, Thomas Reerink, Clement Rousset, Yohan Ruprich-Robert, Philippe Le Sager, Torben Schmith, Roland Schrödner, Federico Serva, Valentina Sicardi, Marianne Sloth Madsen, Benjamin Smith, Tian Tian, Etienne Tourigny, Petteri Uotila, Martin Vancoppenolle, Shiyu Wang, David Wårlind, Ulrika Willén, Klaus Wyser, Shuting Yang, Xavier Yepes-Arbós, and Qiong Zhang
Geosci. Model Dev., 15, 2973–3020, https://doi.org/10.5194/gmd-15-2973-2022, https://doi.org/10.5194/gmd-15-2973-2022, 2022
Short summary
Short summary
The Earth system model EC-Earth3 is documented here. Key performance metrics show physical behavior and biases well within the frame known from recent models. With improved physical and dynamic features, new ESM components, community tools, and largely improved physical performance compared to the CMIP5 version, EC-Earth3 represents a clear step forward for the only European community ESM. We demonstrate here that EC-Earth3 is suited for a range of tasks in CMIP6 and beyond.
Twan van Noije, Tommi Bergman, Philippe Le Sager, Declan O'Donnell, Risto Makkonen, María Gonçalves-Ageitos, Ralf Döscher, Uwe Fladrich, Jost von Hardenberg, Jukka-Pekka Keskinen, Hannele Korhonen, Anton Laakso, Stelios Myriokefalitakis, Pirkka Ollinaho, Carlos Pérez García-Pando, Thomas Reerink, Roland Schrödner, Klaus Wyser, and Shuting Yang
Geosci. Model Dev., 14, 5637–5668, https://doi.org/10.5194/gmd-14-5637-2021, https://doi.org/10.5194/gmd-14-5637-2021, 2021
Short summary
Short summary
This paper documents the global climate model EC-Earth3-AerChem, one of the members of the EC-Earth3 family of models participating in CMIP6. We give an overview of the model and describe in detail how it differs from its predecessor and the other EC-Earth3 configurations. The model's performance is characterized using coupled simulations conducted for CMIP6. The model has an effective equilibrium climate sensitivity of 3.9 °C and a transient climate response of 2.1 °C.
Stelios Myriokefalitakis, Matthias Gröger, Jenny Hieronymus, and Ralf Döscher
Ocean Sci., 16, 1183–1205, https://doi.org/10.5194/os-16-1183-2020, https://doi.org/10.5194/os-16-1183-2020, 2020
Short summary
Short summary
Global inorganic and organic nutrient deposition fields are coupled to PISCES to investigate their effect on ocean biogeochemistry. Pre-industrial deposition fluxes are lower compared to the present day, resulting in lower oceanic productivity. Future changes result in a modest decrease in the nutrients put into the global ocean. This work provides a first assessment of the atmospheric organic nutrients' contribution, highlighting the importance of their representation in biogeochemistry models.
Klaus Wyser, Twan van Noije, Shuting Yang, Jost von Hardenberg, Declan O'Donnell, and Ralf Döscher
Geosci. Model Dev., 13, 3465–3474, https://doi.org/10.5194/gmd-13-3465-2020, https://doi.org/10.5194/gmd-13-3465-2020, 2020
Short summary
Short summary
The EC-Earth model used for CMIP6 is found to have a higher equilibrium climate sensitivity (ECS) than its predecessor used for CMIP5. In a series of sensitivity experiments, we investigate which model updates since CMIP5 have contributed to the increase in ECS. The main reason for the higher sensitivity in the EC-Earth model is the improved representation of the aerosol–radiation and aerosol–cloud interactions.
R. Döscher, T. Vihma, and E. Maksimovich
Atmos. Chem. Phys., 14, 13571–13600, https://doi.org/10.5194/acp-14-13571-2014, https://doi.org/10.5194/acp-14-13571-2014, 2014
Short summary
Short summary
The article reviews progress in understanding of the Arctic sea ice decline. Processes are revisited from an atmospheric, ocean and sea ice perspective. There is strong evidence for decisive atmospheric drivers of sea ice change. Large-scale ocean influences on the Arctic Ocean hydrology and circulation are highly evident. Ocean heat fluxes are clearly impacting the ice margins. Little indication exists for a direct decisive influence of the warming ocean on the central Arctic sea ice cover.
P. Berg, R. Döscher, and T. Koenigk
Geosci. Model Dev., 6, 849–859, https://doi.org/10.5194/gmd-6-849-2013, https://doi.org/10.5194/gmd-6-849-2013, 2013
Ralf Döscher, Mario Acosta, Andrea Alessandri, Peter Anthoni, Thomas Arsouze, Tommi Bergman, Raffaele Bernardello, Souhail Boussetta, Louis-Philippe Caron, Glenn Carver, Miguel Castrillo, Franco Catalano, Ivana Cvijanovic, Paolo Davini, Evelien Dekker, Francisco J. Doblas-Reyes, David Docquier, Pablo Echevarria, Uwe Fladrich, Ramon Fuentes-Franco, Matthias Gröger, Jost v. Hardenberg, Jenny Hieronymus, M. Pasha Karami, Jukka-Pekka Keskinen, Torben Koenigk, Risto Makkonen, François Massonnet, Martin Ménégoz, Paul A. Miller, Eduardo Moreno-Chamarro, Lars Nieradzik, Twan van Noije, Paul Nolan, Declan O'Donnell, Pirkka Ollinaho, Gijs van den Oord, Pablo Ortega, Oriol Tintó Prims, Arthur Ramos, Thomas Reerink, Clement Rousset, Yohan Ruprich-Robert, Philippe Le Sager, Torben Schmith, Roland Schrödner, Federico Serva, Valentina Sicardi, Marianne Sloth Madsen, Benjamin Smith, Tian Tian, Etienne Tourigny, Petteri Uotila, Martin Vancoppenolle, Shiyu Wang, David Wårlind, Ulrika Willén, Klaus Wyser, Shuting Yang, Xavier Yepes-Arbós, and Qiong Zhang
Geosci. Model Dev., 15, 2973–3020, https://doi.org/10.5194/gmd-15-2973-2022, https://doi.org/10.5194/gmd-15-2973-2022, 2022
Short summary
Short summary
The Earth system model EC-Earth3 is documented here. Key performance metrics show physical behavior and biases well within the frame known from recent models. With improved physical and dynamic features, new ESM components, community tools, and largely improved physical performance compared to the CMIP5 version, EC-Earth3 represents a clear step forward for the only European community ESM. We demonstrate here that EC-Earth3 is suited for a range of tasks in CMIP6 and beyond.
Twan van Noije, Tommi Bergman, Philippe Le Sager, Declan O'Donnell, Risto Makkonen, María Gonçalves-Ageitos, Ralf Döscher, Uwe Fladrich, Jost von Hardenberg, Jukka-Pekka Keskinen, Hannele Korhonen, Anton Laakso, Stelios Myriokefalitakis, Pirkka Ollinaho, Carlos Pérez García-Pando, Thomas Reerink, Roland Schrödner, Klaus Wyser, and Shuting Yang
Geosci. Model Dev., 14, 5637–5668, https://doi.org/10.5194/gmd-14-5637-2021, https://doi.org/10.5194/gmd-14-5637-2021, 2021
Short summary
Short summary
This paper documents the global climate model EC-Earth3-AerChem, one of the members of the EC-Earth3 family of models participating in CMIP6. We give an overview of the model and describe in detail how it differs from its predecessor and the other EC-Earth3 configurations. The model's performance is characterized using coupled simulations conducted for CMIP6. The model has an effective equilibrium climate sensitivity of 3.9 °C and a transient climate response of 2.1 °C.
Stelios Myriokefalitakis, Matthias Gröger, Jenny Hieronymus, and Ralf Döscher
Ocean Sci., 16, 1183–1205, https://doi.org/10.5194/os-16-1183-2020, https://doi.org/10.5194/os-16-1183-2020, 2020
Short summary
Short summary
Global inorganic and organic nutrient deposition fields are coupled to PISCES to investigate their effect on ocean biogeochemistry. Pre-industrial deposition fluxes are lower compared to the present day, resulting in lower oceanic productivity. Future changes result in a modest decrease in the nutrients put into the global ocean. This work provides a first assessment of the atmospheric organic nutrients' contribution, highlighting the importance of their representation in biogeochemistry models.
Klaus Wyser, Twan van Noije, Shuting Yang, Jost von Hardenberg, Declan O'Donnell, and Ralf Döscher
Geosci. Model Dev., 13, 3465–3474, https://doi.org/10.5194/gmd-13-3465-2020, https://doi.org/10.5194/gmd-13-3465-2020, 2020
Short summary
Short summary
The EC-Earth model used for CMIP6 is found to have a higher equilibrium climate sensitivity (ECS) than its predecessor used for CMIP5. In a series of sensitivity experiments, we investigate which model updates since CMIP5 have contributed to the increase in ECS. The main reason for the higher sensitivity in the EC-Earth model is the improved representation of the aerosol–radiation and aerosol–cloud interactions.
R. Döscher, T. Vihma, and E. Maksimovich
Atmos. Chem. Phys., 14, 13571–13600, https://doi.org/10.5194/acp-14-13571-2014, https://doi.org/10.5194/acp-14-13571-2014, 2014
Short summary
Short summary
The article reviews progress in understanding of the Arctic sea ice decline. Processes are revisited from an atmospheric, ocean and sea ice perspective. There is strong evidence for decisive atmospheric drivers of sea ice change. Large-scale ocean influences on the Arctic Ocean hydrology and circulation are highly evident. Ocean heat fluxes are clearly impacting the ice margins. Little indication exists for a direct decisive influence of the warming ocean on the central Arctic sea ice cover.
P. Berg, R. Döscher, and T. Koenigk
Geosci. Model Dev., 6, 849–859, https://doi.org/10.5194/gmd-6-849-2013, https://doi.org/10.5194/gmd-6-849-2013, 2013
Related subject area
Approach: Numerical Models | Depth range: Surface | Geographical range: Deep Seas: Arctic Ocean | Phenomena: Sea Ice
A comparison between gradient descent and stochastic approaches for parameter optimization of a sea ice model
H. Sumata, F. Kauker, R. Gerdes, C. Köberle, and M. Karcher
Ocean Sci., 9, 609–630, https://doi.org/10.5194/os-9-609-2013, https://doi.org/10.5194/os-9-609-2013, 2013
Cited articles
Alexander, M., Bhatt, U., Walsh, J., Timlin, M., Miller, J., and Scott, J.: The atmospheric response to realistic Arctic sea ice anomalies in an AGCM during winter, J. Clim., 17, 890–905, https://doi.org/10.1175/1520-0442(2004)017<0890:TARTRA>2.0.CO;2, 2004.
Blanchard-Wrigglesworth, E., Armour, K. C., Bitz, C. M., and DeWeaver, E.: Persistence and Inherent Predictability of Arctic Sea Ice in a GCM Ensemble and Observations, J. Clim., 24, 231–250, https://doi.org/10.1175/2010JCLI3775.1, 2011.
Cassano, J. J., Higgins, M. E., and Seefeldt, M. W.: Performance of the Weather Research and Forecasting Model for Month-Long Pan-Arctic Simulations, Mon. Wea. Rev., 139, 3469–3488, https://doi.org/10.1175/MWR-D-10-05065.1, 2011.
Chapman, W. L. and Walsh, J. E.: Simulations of Arctic Temperature and Pressure by Global Coupled Models, J. Clim., 20, 609–632, https://doi.org/10.1175/JCLI4026.1, 2007:
Comiso, J. C., Parkinson, C. L., Gersten, R., and Stock, L.: Accelerated decline in the Arctic sea ice cover, Geophys. Res. Lett., 35, L01703, https://doi.org/10.1029/2007GL031972, 2008.
Devasthale, A., Koenigk, T., Sedlar, J., and Fetzer, E. J.: The thermodynamic state of the Arctic atmosphere observed by AIRS: comparisons during the record minimum sea-ice extents of 2007 and 2012, Atmos. Chem. Phys. Discuss., 13, 177–199, https://doi.org/10.5194/acpd-13-177-2013, 2013.
Dorn, W. , Dethloff, K. , Rinke, A., and Kurgansky, M.: The recent decline of the Arctic summer sea-ice cover in the context of internal climate variability, The Open Atmospheric Science Journal, 2 , 91–100, https://doi.org/10.2174/1874282300802010091, 2008.
Dorn, W., Dethloff, K., and Rinke, A.: Limitations of a coupled regional climate model in the reproduction of the observed Arctic sea-ice retreat, The Cryosphere, 6 , 985–998, https://doi.org/10.5194/tc-6-985-2012, 2012.
Döscher, R., Willen, U., Jones, C., Rutgersson, A., Meier, H. E. M., and Hansson, U.: The development of the coupled ocean-atmosphere model RCAO, Boreal. Environ. Res., 7, 183–192, 2002.
Döscher, R., Wyser, K., Meier, H., Qian, M., and Redler, R.: Quantifying Arctic Contributions to Climate Predictability in a Regional Coupled Ocean-Ice-Atmosphere Model, Clim. Dynam., 34, 1157–1176, https://doi.org/10.1007/s00382-009-0567-y, 2010.
Francis, J. A. and Hunter, E.: New Insight Into the Disappearing Arctic Sea Ice, Eos Trans. AGU, 87, 509–511, https://doi.org/10.1029/2006EO460001, 2006.
Gerdes, R. and Köberle, C.: Comparison of Arctic sea ice thickness variability in IPCC Climate of the 20th Century experiments and in ocean – sea ice hindcasts, J. Geophys. Res., 112, C04S13, https://doi.org/10.1029/2006jc003616, 2007.
Graversen, R. G., Mauritsen, T., Drijfhout, S., Tjernström, M., and Mårtensson, S.: Warm winds from the Pacific caused extensive Arctic sea-ice melt in summer 2007, Clim. Dyn., 36, 2103–2112, https://doi.org/10.1007/s00382-010-0809-z, 2010.
Holland, M. M., Bitz, C. M., and Tremblay, B.: Future abrupt reductions in the summer Arctic sea ice, Geophys. Res. Lett., 33, L23503, https://doi.org/10.1029/2006GL028024, 2006.
Hunke, E. C. and Dukowicz, J. K.: An elastic-viscous-plastic model for sea ice dynamics, J. Phys. Oceanogr., 27, 1849–1867, https://doi.org/10.1175/1520-0485(1997)027<1849:AEVPMF>2.0.CO;2, 1997.
IPCC: Climate Change 2007 – Impacts, Adaptation and Vulnerability Contribution of Working Group II to the Fourth Assessment Report of the IPCC (978 0521 88010-7 Hardback; 978 0521 70597-4 Paperback), 2007.
Jones, C. G., Willén, U., Ullerstig, A., and Hansson, U.: The Rossby Centre Regional Atmospheric Climate Model – Part 1: model climatology and performance for the present climate over Europe, Ambio, 33, 199–210, 2004a.
Jones, C. G., Wyser, K., Ullerstig, A., and Willén, U.: The Rossby Centre Regional Atmospheric Climate model – Part 2: application to the Arctic climate, Ambio, 33, 211–220, 2004b.
Kauker, F., Kaminski, T., Karcher, M., Giering, R., Gerdes, R., and Vo{ß}beck, M.: Adjoint analysis of the 2007 all time Arctic sea-ice minimum, Geophys. Res. Lett., 36, L03707, https://doi.org/10.1029/2008GL036323, 2009.
Kay, J. E., L'Ecuyer, T., Gettelman, A., Stephens, G., and O'Dell, C.: The contribution of cloud and radiation anomalies to the 2007 Arctic sea ice extent minimum, Geophys. Res. Lett., 35, L08503, https://doi.org/10.1029/2008GL033451, 2008.
Kjellström, E., Bärring, L., Gollvik, S., Hansson, U., Jones, C., Samuelsson, P., Rummukainen, M., Ullerstig, A., Willén, U., and Wyser, K.: A 140-year simulation of European climate with the new version of the Rossby Centre regional atmospheric climate model (RCA3), SMHI reports meteorology and climatology RMK, 108, 54 pp., 2005.
Koenigk, T., Mikolajewicz, U., Haak, H., and Jungclaus, J.: Variability of Fram Strait sea ice export: causes, impacts and feedbacks in a coupled climate model, Clim. Dyn., 26, 17–34, 2006.
Koenigk, T., Döscher, R., and Nikulin, G.: Arctic future scenario experiments with a coupled regional climate model, Tellus A, 63, 69–86, https://doi.org/10.1111/j.1600-0870.2010.00474.x, 2011.
Køltzow, M.: The effect of a new snow and sea ice albedo scheme on regional climate model simulations, J. Geophys. Res., 112, D07110, https://doi.org/10.1029/2006JD007693, 2007.
Kwok, R.: Summer sea ice motion from the 18 GHz channel of AMSR-E and the exchange of sea ice between the Pacific and Atlantic sectors, Geophys. Res. Lett., 35, L03504, https://doi.org/10.1029/2007GL032692, 2008
L'Heureux, M. L., Kumar, A., Bell, G. D., Halpert, M. S., and Higgins, R. W.: Role of the Pacific-North American (PNA) pattern in the 2007 Arctic sea ice decline, Geophys. Res. Lett., 35, L20701, https://doi.org/10.1029/2008GL035205, 2008.
Maslanik, J. A., Fowler, C., Stroeve, J., Drobot, S., Zwally, H. J., Yi, D., and Emery, W. J.: A younger, thinner Arctic ice cover: Increased potential for rapid, extensive sea ice loss, Geophys. Res. Lett., 34, L24501, https://doi.org/10.1029/2007GL032043, 2007.
Massonnet, F., Fichefet, T., Goosse, H., Bitz, C. M., Philippon-Berthier, G., Holland, M. M., and Barriat, P.-Y.: Constraining projections of summer Arctic sea ice, The Cryosphere Discuss., 6, 2931–2959, https://doi.org/10.5194/tcd-6-2931-2012, 2012.
Mårtensson, S., Meier, H. E. M., Pemberton, P., and Haapala, J.: Ridged sea ice characteristics in the Arctic from a coupled multicategory sea ice model, J. Geophys. Res., 117, C00D15, https://doi.org/10.1029/2010JC006936, 2012.
Meier, H. E. M., Döscher, R., and Faxén, T.: A multiprocessor coupled ice-ocean model for the Baltic Sea: application to salt inflow, J. Geophys. Res., 108, 3273, https://doi.org/10.1029/2000JC000521, 2003.
Ogi, M., Rigor, I. G., McPhee, M. G., and Wallace, J. M.: Summer retreat of Arctic sea ice: Role of summer winds, Geophys. Res. Lett., 35, L24701, https://doi.org/10.1029/2008GL035672, 2008.
Overland, J. E. and Wang, M.: Large-scale atmospheric circulation changes are associated with the recent loss of Arctic sea ice, Tellus A, 62, 1–9, https://doi.org/10.1111/j.1600-0870.2009.00421.x, 2010.
Overland, J. E., Wang, M., and Salo, S.: The recent Arctic warm period, Tellus A, 60, 589–597, https://doi.org/10.1111/j.1600-0870.2008.00327.x, 2008.
Paquin, J.-P., Paquin, R., Döscher, L., Sushama, T., and Königk, T.: Causes and consequences of mid-21st Century Rapid Ice Loss Events simulated by the Rossby Centre Regional Atmosphere-Ocean model, submitted, 2013.
Perovich, D. K., Richter-Menge, J. A., Jones, K. F., and Light, B.: Sunlight, water, and ice, Extreme Arctic sea ice melt during the summer of 2007, Geophys. Res. Lett., 35, L11501, https://doi.org/10.1029/2008GL034007, 2008.
Redler, R., Valcke, S., and Ritzdorf, H.: OASIS4-a coupling software for next generation earth system modelling, Geosci. Model Develop., 3, 87–104, 2010.
Samuelsson, P., Gollvik, S., and Ullerstig, A.: The land-surface scheme of the Rossby Centre regional atmospheric climate model (RCA3), Report in meteorology 122, SMHI, SE-601 76 Norrköping, Sweden, 2006.
Schweiger, A. J., Zhang, J., Lindsay, R. W., and Steele, M.: Did unusually sunny skies help drive the record sea ice minimum of (2007, Geophys. Res. Lett., 35, L10503, https://doi.org/10.1029/2008GL033463, 2008
Semtner, A. J.: A model for the thermodynamic growth of sea ice in numerical investigations of climate, J. Phys. Oceanogr., 6, 27–37, 1976.
Serreze, M., Andrew, C., and Barrett, P.: Characteristics of the Beaufort Sea High, J. Climate, 24, 159–182, https://doi.org/10.1175/2010JCLI3636.1, 2011.
Shindell, D. and G. Faluvegi: Climate response to regional radiative forcing during the twentieth century, Nature Geosci., 2, 294–300, https://doi.org/10.1038/ngeo473, 2009
Steele, M., Rebecca, M., and Wendy, E.: PHC: A Global Ocean Hydrography with a High-Quality Arctic Ocean, J. Climate, 14, 2079–2087. https://doi.org/10.1175/1520-0442(2001)014<2079:PAGOHW>2.0.CO;2, 2001
Stroeve, J., Serreze, M., Drobot, S., Gearhead, S., Holland, M., Maslanik, J., Meier, W., and Scambos, T.: Arctic sea ice extent plummets in 2007, Eos, Trans. Amer. Geophys. Union, 89, 13–14, 2008.
Tietsche, S., Notz, D., Jungclaus, J. H., and Marotzke, J.: Recovery mechanisms of Arctic summer sea ice, Geophys. Res. Lett. 38, L02707, https://doi.org/10.1029/2010GL045698, 2011.
Vancoppenolle, M., Fichefet, T., Goosse, H., Bouillon,S., König Beatty, C., and Morales Maqueda, M. A.: LIM3, an advanced sea-ice model for climate simulation and operational oceanography, Mercator Ocean Quarterly Newsletter, 28, 16–21., 2008.
Walter, K., Ute L., and Klaus F.: A Response Climatology of Idealized Midlatitude Thermal Forcing Experiments with and without a Storm Track, J. Clim., 14, 467–484, https://doi.org/10.1175/1520-0442(2001)014<0467:ARCOIM>2.0.CO;2, 2001.
Wang, J., Zhang, J., Watanabe, E., Ikeda, M., Mizobata, K., Walsh, J. E., Bai, X., and Wu, B.: Is the dipole anomaly a major driver to record lows in Arctic summer sea ice extent?, Geophys. Res. Lett., 36, L05706, https://doi.org/10.1029/2008GL036706, 2009.
Woodgate, R. A., Weingartner, T., and Lindsay, R.: The 2007 Bering Strait Oceanic Heat Flux and anomalous Arctic Sea-ice Retreat, Geophys. Res. Lett., 37, L01602, https://doi.org/10.1029/2009GL041621, 2010.
Wu, B., Wang, J., and Walsh, J. E.: Dipole Anomaly in the Winter Arctic Atmosphere and Its Association with Sea Ice Motion, J. Clim., 19, 210–225, 2006.
Zhang, X. and Walsh, J. E.: Towards a seasonally ice-covered Arctic Ocean: Scenarios from the IPCC AR4 simulations, J. Clim., 19, 1730–1747, 2006.
Zhang, X., Sorteberg, A., Zhang, J., Gerdes, R., and Comiso, J. C.: Recent radical shifts of atmospheric circulations and rapid changes in Arctic climate system, Geophys. Res. Lett., 35, L22701, https://doi.org/10.1029/2008GL035607, 2008.