Hinge‐line migration of Petermann Gletscher, north Greenland, detected using satellite‐radar interferometry

• Main Author: Eric Rignot
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Published: 1998
• Subjects: Awl; Greenland; Petermann Gletscher; glacier; North Greenland; Petermann gletscher
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.612.807; http://trs-new.jpl.nasa.gov/dspace/bitstream/2014/19518/1/98-0936.pdf

ABSTRACT. The synthetic-aperture radar interferometry technique is used to detect the migration of the limit of tidal flexing, or hinge line, of the floating ice tongue of Petermann Gletscher, a major outlet glacier of north Greenland. The hinge line is detected automat-ically from differential interferograms using a model fitting technique based on an elastic beam theory. The statistical noise of the model fit is less than 3 mm, and the hinge line is mapped with a precision of 30 m. Following automatic registration of multi-date image data to a precision of 5 m, hinge-line migration is subsequently detected with a precision of 40 m in the horizontal plane across the glacier width. The results show that the hinge line of Petermann Gletscher migrates back and forth with tide by f 7 0 m, in excellent agreement with the migration calculated from ocean tides predicted by a tidal model combined with the glacier surface and basal slope measured by an ice-sounding radar. Superimposed on the short-term hinge-line migration due to tide, we detect a hinge line retreat of 270 m in 3.87 years which varies across the glacier width by f120 m. The retreat suggests glacier thinning at a rate of 7 8 f 3 5 cm ice awl. Coincidentally, an analysis of ice volume fluxes indicates that the hinge line ice flux of Petermann Gletscher exceeds its balance flux by 0. 8 8 f l krn3icea-', which in turn implies glacier thinning at 8 3 f 9 5 cm ice a- ' in the glacier lower reaches. Both methods therefore suggest that Petermann Gletscher is currently losing mass to the ocean. 1