Snow-ice contribution to the structure of sea ice in the Amundsen Sea, Antarctica

• Published in: Annals of Glaciology
• Main Authors: Tian, Lijun, Gao, Yongli, Weissling, Blake, Ackley, Stephen F.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Cambridge University Press (CUP) 2020
• Subjects: Antarctic; Southern Ocean; Amundsen Sea; Annals of Glaciology; Antarc*; Antarctica; Sea ice
• Online Access: http://dx.doi.org/10.1017/aog.2020.55; https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0260305520000555

Abstract The widespread occurrence of snow-ice formation on the pack ice plays a critical role in the mass balance of Antarctic sea ice. The stable isotope composition, ice texture and salinity of eight ice cores, obtained from the Amundsen Sea during the Oden Southern Ocean 2010/11 expedition from late December 2010 to January 2011, were investigated to illustrate the snow-ice growth process and its contribution to sea-ice development. Most previous research has utilized δ 18 O as an index tracer to determine the percentages of core length that contain meteoric water, i.e. snow ice. However, this standard practice of snow-ice identification might be biased due to normally low-resolution isotopic measurements and mixing/diffusion processes between the snow ice and underlying ice layers. Snow-ice contributions in these ice cores based instead on an updated isotope mixing model are also presented. Depth profiles of ice texture and salinity are described to serve as representations of the structures of these ice cores. Our isotope mixing model produced an average of 15.9% snow-ice contribution for pack ice in the Amundsen Sea, and meteoric water occupying 40% of snow-ice mass for all ice stations. These results are compared to previous investigations of snow-ice occurrence around Antarctica.