Annals of Glaciology 51(55) 2010 49 Deformation and failure of the ice bridge on the Wilkins Ice Shelf

• Main Authors: A. Humbert, D. Gross, M. Braun, M. R. Van, Den Broeke, D. G. Vaughan, W. J. Van De Berg
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Subjects: Charcot; Charcot Island; Wilkins; Wilkins Ice Shelf; Antarc*; Antarctica; Ice Shelf
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.725.2794; http://www.staff.science.uu.nl/%7Ebroek112/home.php_files/Publications_MvdB/2010_Humbert_AnnGlac.pdf

Antarctica, to two confining islands eventually collapsed in early April 2009. In the month preceding the collapse, we observed deformation of the ice bridge by means of satellite imagery and from an in situ GPS station. TerraSAR-X images (acquired in stripmap mode) were used to compile a time series. The ice bridge bent most strongly in its narrowest part (westerly), while the northern end (near Charcot Island) shifted in a northeasterly direction. In the south, the ice bridge experienced compressive strain parallel to its long axis. GPS position data were acquired a little south of the narrowest part of the ice bridge from 19 January 2009. Analysis of these data showed both cyclic and monotonic components of motion. Meteorological data and re-analysis of the output of weather-prediction models indicated that easterly winds were responsible for the cyclic motion component. In particular, wind stress on the rough ice melange that occupied the area to the east exerted significant pressure on the ice bridge. The collapse of the ice bridge began with crack formation in the southern section parallel to the long axis of the ice bridge and led to shattering of the southern part. Ultimately, the narrowest part, only 900m wide, ruptured. The formation of many small icebergs released energy of>125×106 J.