Sources of multi-decadal variability in Arctic sea ice extent

• Published in: Environmental Research Letters
• Main Authors: J J Day, J C Hargreaves, J D Annan, A Abe-Ouchi
• Format: Article in Journal/Newspaper
• Language: English
• Published: IOP Publishing 2012
• Subjects: sea ice extent; Atlantic multi-decadal oscillation; Arctic oscillation; Atlantic meridional overturning circulation; Arctic; climate variability; Environmental technology. Sanitary engineering; TD1-1066; Environmental sciences; GE1-350; Science; Q; Physics; QC1-999; Sea ice
• Online Access: https://doi.org/10.1088/1748-9326/7/3/034011; https://doaj.org/article/dd36831671be4b58868dd49df5b072e4

The observed dramatic decrease in September sea ice extent (SIE) has been widely discussed in the scientific literature. Though there is qualitative agreement between observations and ensemble members of the Third Coupled Model Intercomparison Project (CMIP3), it is concerning that the observed trend (1979–2010) is not captured by any ensemble member. The potential sources of this discrepancy include: observational uncertainty, physical model limitations and vigorous natural climate variability. The latter has received less attention and is difficult to assess using the relatively short observational sea ice records. In this study multi-centennial pre-industrial control simulations with five CMIP3 climate models are used to investigate the role that the Arctic oscillation (AO), the Atlantic multi-decadal oscillation (AMO) and the Atlantic meridional overturning circulation (AMOC) play in decadal sea ice variability. Further, we use the models to determine the impact that these sources of variability have had on SIE over both the era of satellite observation (1979–2010) and an extended observational record (1953–2010). There is little evidence of a relationship between the AO and SIE in the models. However, we find that both the AMO and AMOC indices are significantly correlated with SIE in all the models considered. Using sensitivity statistics derived from the models, assuming a linear relationship, we attribute 0.5–3.1%/decade of the 10.1%/decade decline in September SIE (1979–2010) to AMO driven variability.