Surface flow velocity on Bowdoin Gletscher, Greenland in July 2013

The surface motion of the glacier was measured by surveying 7 stakes (1.5 m long aluminium poles) installed in the ice in the lower part of Bowdoin Gletscher. We used dual-frequency GPS receivers and antennas (GNSS GEM-1) to measure the three-dimensional positions of the stakes. One antenna was fixed to solid rock on the eastern bank of the glacier as a reference station. At B1301-1303, the antennae were mounted on the stakes and operated every seconds. The stakes at B13T1-B13T4 were surveyed with the same devices for 30 minutes. These data were processed in static mode by the GPS software (RTKLIB) to compute the position of the stakes (every 15 minutes in stakes B1301-1303). Measurement errors were estimated below 10 mm.