The dynamics of Daugaard Jensen Gletscher from 1985 to 2011
17 September 2013
Daugaard Jensen Gletscher, Greenland, is a large tidewater glacier covering an estimated 4% of the Greenland ice sheet. In this study the team investigate whether recent changes in the dynamics and mass balance of this sector of the Greenland ice sheet are reflected in the behaviour of this particular glacier.
To identify the dynamic characteristics and calving behaviour of this glacier, a 26 year time series of surface velocities and frontal positions, spanning the period 1985 to 2011, was generated by applying intensity feature tracking to ERS SAR and Envisat ASAR, Landsat-5 TM band 4 and Landsat-7 ETM band 8 image pairs. Before tracking Landsat-5 and 7 images were re-sampled using a quadratic interpolation and re-projected to the polar stereographic coordinate system. The SAR images were tracked in slant-range and azimuth geometry after 1x5 multi-looking to a pixel size of ~8mx20 m. This ratio of multi-looking results in approximately square pixels when the displacements are converted to ground range. The time series confirms that flow speeds remained stable and reveals a persistent summer acceleration of up to 10% over the lower 10km of the glacier. The front of the 6 km floating tongue fluctuates by little more than the average size of calved icebergs, 1 km.