Glacier surface velocity

The speed of the glacier is mainly dependent on the ice thickness, surface slope, the thickness and properties of basal sediments, and the temperature of the ice, but also on the weather and the season. Surface velocities have been measured for selected outlet glaciers during the summer, using GPS instruments, and velocity maps have been compiled from satellite data. The summer velocity is typically twice the winter velocity. The larger outlet glaciers move approximately 1 m/day in summer. The velocity measurements data set main­tained by the Institute of Earth Sciences at the University of Iceland and ice surface maps are important for the study of surges.

 

Velocity maps of the Icelandic glaciers, including Vatnajökull ice cap, estimated from satellite data by the Austrian company ENVEO, in cooperation with the Icelandic Meteorological Office and the Institute of Earth Scienes, University of Iceland.

Velocity maps of the Icelandic glaciers, including Vatnajökull ice cap, estimated from satellite data by the Austrian company ENVEO, in cooperation with the Icelandic Meteorological Office and the Institute of Earth Scienes, University of Iceland.

Two velocity maps of Skeiðarárjökull derived from satellite images, showing the variation in glacier surface velocity. The horizontal velocity field of the outlet glacier at the end of December (a) and during the beginning of the 1996 jökulhlaup (b). The blue line shows the estimated flood path. Source: Magnússon et al. (2007).

Two velocity maps of Skeiðarárjökull derived from satellite images, showing the variation in glacier surface velocity. The horizontal velocity field of the outlet glacier at the end of December (a) and during the beginning of the 1996 jökulhlaup (b). The blue line shows the estimated flood path. Source: Magnússon et al. (2007).