E 2008, by the American Society of Limnology and Oceanography, Inc. High-latitude oceanography using the Autosub autonomous underwater vehicle

• Main Authors: Keith W. Nicholls, E. Povl Abrahamsen, Karen J. Heywood, Kate Stansfield, Svein Østerhus
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Subjects: Fimbul Ice Shelf; Ronne Ice Shelf; Antarc*; Antarctica; Filchner Ronne Ice Shelf; Filchner-Ronne Ice Shelf; Ice Sheet; Ice Shelf
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.224.216; http://www.aslo.org/lo/toc/vol_53/issue_5_part_2/2309.pdf

A combination of measurements from Autosub, an autonomous underwater vehicle, and ship-based instruments are used to describe the oceanographic conditions beneath Fimbul Ice Shelf, Antarctica. The data show an intricate oceanographic regime that is suggestive of variability at seasonal or longer time scales. Results from a numerical model of the flow beneath the ice shelf lend support to a strong seasonal variability, and data from instruments moored beneath the ice shelf show substantial temporal variations. The Autosub data indicate temperatures within the cavity somewhat lower than our model results would suggest; thus, our modeled melt rates (average of 0.85 m yr21) might be overestimates, although they are substantially lower than from previously published model studies (4.9 and 1.9 m yr21). The contribution of ice shelf melt in the freshwater balance of the waters upstream of the climatically important Filchner-Ronne Ice Shelf needs to be reassessed. Antarctica houses the greatest ice sheet of the Earth’s cryosphere. It contains the majority of the planet’s freshwater, which, if all released to the sea, would cause a sea-level rise of over 50 m (Lythe and Vaughan 2001). The ice sheet also plays active, though by no means fully