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.本研究通过对安装于鲍多因冰川（Bowdoin Gletscher）下段冰体中的7根测杆（1.5米长铝制杆体）进行测量，获取冰川表面运动数据。我们采用双频GPS接收机与天线（GNSS GEM-1）测定各测杆的三维位置。其中一根天线固定于冰川东岸的基岩上，作为基准站。对于B1301至B1303号测杆，天线安装于测杆之上，按每秒一次的频次开展作业。针对B13T1至B13T4号测杆，我们使用同款设备开展了30分钟的测量工作。我们通过GPS处理软件（RTKLIB）以静态模式处理上述数据，以解算测杆的位置信息（其中B1301至B1303号测杆的位置解算频次为每15分钟一次）。经估算，本次测量的误差低于10毫米。