Ice flows from the high interior to the margin of the Greenland ice sheet where it either melts or is lost to iceberg calving. Ice flows faster in a warmer climate, because meltwater originating from the surface reduces friction at the bottom of the ice sheet. Increased iceberg calving from outlet glaciers, often termed the ice-dynamic mass loss, is responsible for a substantial part of the mass loss of the Greenland ice sheet.
We can quantify the ice-dynamic mass loss by combining observations of ice flow (ice surface velocities) and ice thickness. Maps of ice surface velocities for the Greenland Ice Sheet are derived from Synthetic Aperture Radar (SAR) data mainly from ESA Sentinel-1. We use offset-tracking to measure the horizontal velocity components and apply the operational interferometric post processing chain IPP for the analysis. The IPP processor has been developed by the National Space Institute at the Technical University of Denmark (DTU Space).
The ESA Sentinel-1 mission observes the Greenland ice sheet margin every 6 days, while a dedicated campaign in wintertime covers the interior ice sheet. Click here to download Greenland ice sheet surface velocity data.
Morlighem, M., E. Rignot, J. Mouginot, H. Seroussi and E. Larour. 2015.IceBridge BedMachine Greenland, Version 2. Boulder, Colorado USA: NASA DAAC at the National Snow and Ice Data Center.
Morlighem, M., E. Rignot, J. Mouginot, H. Seroussi and E. Larour. 2014. Deeply incised submarine glacial valleys beneath the Greenland Ice Sheet, Nature Geoscience, 7:418-422.
Timelapse of calving glacier in Greenland
Figure: Winter surface velocities [m/day] 2015/2016
derived from ESA Sentinel-1 data for Northeast