Patterns of decadal-scale Arctic warming events in simulated climate
- 561 Downloads
Pronounced positive decadal-scale temperature anomalies occurred in the Arctic region in the first half of the twentieth century, an episode known as the early twentieth century warming (ETCW). Analyzing a 3,000-year unperturbed climate simulation performed with the Max Planck Institute Earth System Model, we demonstrate that internal variability of the Northern Hemisphere climate system is sufficient to reproduce warm events matching the observed ETCW. We perform a superposed epoch analysis on simulated data and identify 26 Arctic warming episodes compatible with the ETCW. The simulated events reproduce, in their ensemble average, magnitude as well as spatial and temporal extent of the observed ETCW. In individual realizations, the ETCW-like events indicate that different patterns of internally generated decadal Arctic warming are possible, including pan-Arctic warming events. We investigate the dynamics that typically lead to the simulated warming events: positive oceanic heat transport anomalies that form in the North Atlantic initialize the warming events and trigger an ocean-ice-albedo feedback in the Barents Sea region. The consequent reduction in sea-ice extent leads to enhanced multi-year surface warming through strengthened ocean heat release to the atmosphere. The oceanic heat transport anomalies reduce to pre-event levels around the year of the maximum warming. However, the warming events typically lasts for another 5–7 years until the sea-ice extent recovers to pre-event conditions.
KeywordsDecadal natural climate variability Arctic climate Superposed epoch analysis Coupled atmosphere–ocean–sea-ice processes Early twentieth century warming
We gratefully acknowledge T. Mauritsen, J. Marotzke and two anonymous reviewers for their comments and recommendations that helped to improve the manuscript. JHJ has received funding from the European Union 7th Framework Programme (FP7 2007–2013) under Grant agreement No. 308299 (NACLIM project). DZ received funding from the Federal Ministry for Education and Research in Germany (BMBF) through the research program “MiKlip” (FKZ:01LP1158A). AB took part in the course “Advanced Scientific Writing” held at the MPI by J. Marotzke and D. Murphy, which helped to further improve the manuscript.
- Bjerknes J (1964) Atlantic air-sea interaction advances in geophysics, vol 10. Academic Press, New York, pp 1–82Google Scholar
- Brovkin V, Lorenz SJ, Jungclaus J, Raddatz T, Timmreck C, Reick CH, Segschneider J, Six K (2010) Sensitivity of a coupled climate-carbon cycle model to large volcanic eruptions during the last millennium. Tellus B, no–no, http://dx.doi.org/10.1111/j.1600-0889.2010.00471.x
- Compo GP, Whitaker JS, Sardeshmukh PD, Matsui N, Allan RJ, Yin X, Gleason BE, Vose RS, Rutledge G, Bessemoulin P, Brönnimann S, Brunet M, Crouthamel RI, Grant AN, Groisman PY, Jones PD, Kruk M, Kruger AC, Marshall GJ, Maugeri M, Mok HY, Nordli Ø, Ross TF, Trigo RM, Wang XL, Woodruff SD, Worley SJ (2011) The twentieth century reanalysis project. Q J R Meteorol Soc 137:1–28. doi: 10.1002/qj.776 CrossRefGoogle Scholar
- Hegerl G, Zwiers FW, Braconnot P, Gillett N, Luo Y, Orsini JM, Nicholls N, Penner J, Stott P (2007) Climate change 2007: the physical science basis. Contribution of Working Group I to the Fourth Assessment Report of the IPCC, chap. Understanding and Attributing Climate Change, 663–745. Cambridge University Press, http://www.ipcc.ch/ipccreports/ar4-wg1.htm
- Jaiser R, Dethloff K, Handorf D, Rinke A, Cohen J (2012) Impact of sea ice cover changes on the Northern Hemisphere atmospheric winter circulation. Tellus A 64 (11595). doi: 10.3402/tellusa.v64i0.11595
- Jungclaus JH, Lorenz SJ, Timmreck C, Reick CH, Brovkin V, Six K, Segschneider J, Giorgetta MA, Crowley TJ, Pongratz J, Krivova NA, Vieira LE, Solanki SK, Klocke D, Botzet M, Esch M, Gayler V, Haak H, Raddatz TJ, Roeckner E, Schnur R, Widmann H, Claussen M, Stevens B, Marotzke J (2010) Climate and carbon-cycle variability over the last millennium. Clim Past 6:723–737CrossRefGoogle Scholar
- Overland JE, Wang M (2005) The third Arctic climate pattern: 1930s and early 2000s Geophys Res Lett 32:L23808Google Scholar
- Overland JE, Wood KR, Wang MY (2011) Warm Arctic-cold continents: climate impacts of the newly open Arctic Sea. Polar Res 30(15787). doi: 10.3402/polar.v30i0.15787
- Roeckner E, et al (2003) The atmosphere general circulation model ECHAM5, part 1: model description. Technical report no. 349: 127 pp, Max-Planck-Institut für MeteorologieGoogle Scholar
- Serreze MC, Barry RG (2011) Processes and impacts of Arctic amplification: a research synthesis. Glob Planetary Chang 77:85–96Google Scholar
- Zhang X, Sorteberg A, Zhang J, Gerdes R, Comiso JC (2008) Recent radical shifts of atmospheric circulations and rapid changes in Arctic climate system. Geophys Res Lett 35:L22701Google Scholar