Annual surface flow velocity on Qaanaaq ice cap, Greenland in 2016-2017

The surface motion of the glacier was measured by surveying 6 stakes (1.5-2.0 m long aluminium poles) installed in the ice of Qaanaaq ice cap. Dual-frequency GPS receivers and antennas (GNSS GEM-1) were used to measure the three-dimensional positions of the stakes. One antenna was fixed on the roof of Qaanaaq Club House as a reference station. At Q1601-Q1606, the antennae were mounted on the stakes and operated for 30 minutes in July 2016 and August 2017. These data were processed in static mode by the GPS software (RTKLIB) to compute the position of the stakes every 30 minutes. Measurement errors were estimated below 10 mm.