Article

Arctic Sea Ice Retreat in 2007 Follows Thinning Trend

Journal of Climate (Impact Factor: 4.9). 01/2009; 22. DOI: 10.1175/2008JCLI2521.1

ABSTRACT The minimum of Arctic sea ice extent in the summer of 2007 was unprecedented in the historical record. A coupled ice–ocean model is used to determine the state of the ice and ocean over the past 29 yr to investigate the causes of this ice extent minimum within a historical perspective. It is found that even though the 2007 ice extent was strongly anomalous, the loss in total ice mass was not. Rather, the 2007 ice mass loss is largely consistent with a steady decrease in ice thickness that began in 1987. Since then, the simulated mean September ice thickness within the Arctic Ocean has declined from 3.7 to 2.6 m at a rate of 0.57 m decade 1 . Both the area coverage of thin ice at the beginning of the melt season and the total volume of ice lost in the summer have been steadily increasing. The combined impact of these two trends caused a large reduction in the September mean ice concentration in the Arctic Ocean. This created conditions during the summer of 2007 that allowed persistent winds to push the remaining ice from the Pacific side to the Atlantic side of the basin and more than usual into the Greenland Sea. This exposed large areas of open water, resulting in the record ice extent anomaly.

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Available from: Axel Schweiger, Jul 10, 2014
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    • "The mean sea ice thickness of the Arctic has been decreasing since the 1980s (Lindsay and Zhang, 2005; Rigor et al., 2004), and the sea ice extent reached minimum values in 2007 and 2008 (Lindsay et al., 2009). "
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    • "The Arctic pack ice region is undergoing dramatic changes due to global warming (e.g., IPCC, 2007; Jeffries and Richter-Menge, 2012). These changes not only affect 5 the extent and thickness of the Arctic sea ice (Lindsay et al., 2009), but also the influence of physical and chemical processes of the aerosols on the regional climate (e.g., Curry et al., 2000; Prenni et al., 2007). Herein, radiative effects of aerosol particles and aerosol–cloud interactions play a substantial role: aerosols interact with solar radiation directly by scattering or absorbing sunlight. "
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    • "Changes in the arctic climate system over the past decades were exceptional in the history of Arctic observations (e.g., Walsh and Chapman 2001, Polyakov et al. 2005, Meier et al. 2007, Belchansky et al. 2008, Lindsay et al. 2009), culminating with the summer of 2012 when the arctic ice retreat broke all records (Overland and Wang 2013). Despite the fundamental importance of high-latitude changes for global climate, there are numerous gaps in our understanding of how the system functions and what forces are driving changes in the Arctic. "
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