A glimpse beneath Antarctic sea ice : Platelet layer volume from multifrequency electromagnetic induction sounding

• Published in: Geophysical Research Letters
• Main Authors: Hunkeler, Priska A., Hoppmann, Mario, Hendricks, Stefan, Kalscheuer, Thomas, Gerdes, Ruediger
• Format: Article in Journal/Newspaper
• Language: English
• Published: Uppsala universitet, Geofysik 2016
• Subjects: Geophysics; Geofysik; Antarctic; Weddell; Weddell Sea; Antarc*; Antarctica; Ice Shelf; Sea ice
• Online Access: http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-270273; https://doi.org/10.1002/2015GL065074

In Antarctica, ice crystals emerge from ice-shelf cavities and accumulate in unconsolidated layers beneath nearby sea ice. Such sub-ice platelet layers form a unique habitat, and serve as an indicator for the state of an ice shelf. However, the lack of a suitable methodology impedes an efficient quantification of this phenomenon on scales beyond point measurements. In this study, we inverted multi-frequency electromagnetic (EM) induction soundings of > 100 km length, obtained on fast ice with an underlying platelet layer in the eastern Weddell Sea. EM-derived platelet-layer thickness and conductivity are consistent with other field observations. Our results further suggest that platelet-layer volume is higher than previously thought in this region, and that platelet-layer ice-volume fraction is proportional to its thickness. We conclude that multi-frequency EM is a suitable tool to determine platelet-layer volume, with the potential to obtain crucial knowledge of associated processes in otherwise inaccessible ice-shelf cavities.