Rapid ice discharge from southeast Greenland glaciers

Abstract

Interferometric synthetic‐aperture radar (InSAR) observations of southeast Greenland glaciers acquired by the Earth Remote Sensing Satellites (ERS‐1/2) in 1996 were combined with ice sounding radar data collected in the late 1990s to estimate a total discharge of 46 ± 3 km 3 ice per year between 62°N and 66°N, which is significantly lower than a mass input of 29 ± 3 km 3 ice per year calculated from a recent compilation of snow accumulation data. Further north, Helheim Glacier discharges 23 ± 1 km 3 /yr vs 30 ± 3 km 3 /yr accumulation; Kangerdlugssuaq Glacier discharges 29 ± 2 km 3 /yr vs 23 ± 2 km 3 /yr; and Daugaard‐Jensen Glacier discharges 10.5 ± 0.6 km 3 /yr vs 10.5 ± 1 km 3 /yr. The mass balance of east Greenland glaciers is therefore dominated by the negative mass balance of southeast Greenland glaciers (−17 ± 4 km 3 /yr), equivalent to a sea level rise of 0.04 ± 0.01 mm/yr. Warmer and drier conditions cannot explain the imbalance which we attribute to long‐term changes in ice dynamics.