1National Institute of Polar Research, 10-3 Midoricho, Tachikawa, Tokyo, 190-8518, Japan
2Scripps Institution of Oceanography, University of California, San Diego, La Jolla, CA 92093, USA
3NASA Goddard Institute for Space Studies, New York, NY 10025, USA
4Meteorological Research Institute, Tsukuba, 305-0052, Japan
5Solar Terrestrial Environment Laboratory, Nagoya University, Nagoya, Japan
6Byrd Polar Research Center, The Ohio State University, Columbus, OH 43210, USA
7Department of Geography, The Ohio State University, Columbus, OH 43210, USA
Received: 28 Sep 2012 – Published in Clim. Past Discuss.: 08 Nov 2012
Abstract. The surface temperature of the Greenland ice sheet is among the most important climate variables for assessing how climate change may impact human societies due to its association with sea level rise. However, the causes of multidecadal-to-centennial temperature changes in Greenland temperatures are not well understood, largely owing to short observational records. To examine these, we calculated the Greenland temperature anomalies (GTA[G-NH]) over the past 800 yr by subtracting the standardized northern hemispheric (NH) temperature from the standardized Greenland temperature. This decomposes the Greenland temperature variation into background climate (NH); polar amplification; and regional variability (GTA[G-NH]). The central Greenland polar amplification factor as expressed by the variance ratio Greenland/NH is 2.6 over the past 161 yr, and 3.3–4.2 over the past 800 yr. The GTA[G-NH] explains 31–35% of the variation of Greenland temperature in the multidecadal-to-centennial time scale over the past 800 yr. We found that the GTA[G-NH] has been influenced by solar-induced changes in atmospheric circulation patterns such as those produced by the North Atlantic Oscillation/Arctic Oscillation (NAO/AO). Climate modeling and proxy temperature records indicate that the anomaly is also likely linked to solar-paced changes in the Atlantic meridional overturning circulation (AMOC) and associated changes in northward oceanic heat transport.
Revised: 15 Feb 2013 – Accepted: 25 Feb 2013 – Published: 08 Mar 2013
Kobashi, T., Shindell, D. T., Kodera, K., Box, J. E., Nakaegawa, T., and Kawamura, K.: On the origin of multidecadal to centennial Greenland temperature anomalies over the past 800 yr, Clim. Past, 9, 583-596, doi:10.5194/cp-9-583-2013, 2013.