2 Is Recent Sea Ice Expansion in the Southern Ocean Anthropogenic?

• Main Authors: X. Qu, J. Boé, Ellen Mosley-thompson, Lonnie G. Thompson
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Subjects: Antarctic; Antarctic Peninsula; Arctic; Bellingshausen Sea; Ross Sea; Southern Ocean; Talos Dome; Victoria Land; West Antarctica; Antarc*; Antarctica; ice core; Sea ice
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.389.4185; http://www.atmos.ucla.edu/csrl/publications/Hall/Qu_et_al_2009a.pdf

Though Arctic sea ice extent has been declining, sea ice in the Southern Ocean has experienced modest expansion since the 1970s. This weak positive trend results from sea ice growth in the western Ross Sea (WRS) that slightly exceeds shrinkage near the western Antarctic Peninsula and in the southern Bellingshausen Sea. While the shrinkage near the western Antarctic Peninsula and in the southern Bellingshausen Sea is consistent with rapid warming in West Antarctica, the growth in the WRS appears contradictory in light of the warming, albeit small, over nearby Northern Victoria Land. Here we present results from an annually resolved ice core suggesting that the WRS sea ice advance may be largely natural in origin. We examine variations of the δD content of the Talos Dome ice core shown to be well correlated with WRS ice cover (the coefficient is-0.53, p<0.008). The δD content has varied irregularly about its long-term mean for the past eight centuries, and does not exhibit any significant trend over the past 150 years, the period of anthropogenic influence on global climate. The very red δD variability