Annual surface flow velocity on Qaanaaq ice cap, Greenland in 2017-2018

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 Q1701-Q1706, the antennae were mounted on the stakes and operated for more than 30 minutes in August 2017 and August 2018. These data were processed in static mode by the GPS software (RTKLIB) to compute the position of the stakes. Measurement errors were estimated below 10 mm.