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

• Published in: Journal of Glaciology
• Main Author: Rignot, Eric
• Format: Article in Journal/Newspaper
• Language: English
• Published: Cambridge University Press (CUP) 1998
• Subjects: Greenland; Petermann Gletscher; glacier; Journal of Glaciology; North Greenland; Petermann gletscher
• Online Access: http://dx.doi.org/10.1017/s0022143000001994; https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0022143000001994

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 longue of Peter-mann Gletscher, a major outlet glacier of north Greenland. The hinge line is detected automatically 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 multidate image data to a precision of 5m, 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 ±70m, 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 ± 120 m. The retreat suggests glacier thinning at a rate of 78 + 35 cm ice a −1 . Coincidentally, an analysis of ice-volume fluxes indicates that the hinge-line ice flux of Petermann Gletscher exceeds its balance flux by 0.88±1km 3 ice a −1 , which in turn implies glacier thinning at 83+95cm ice a −1 in the glacier lower reaches. Both methods therefore suggest that Petermann Gletscher is currently losing mass to the ocean.