Surface flow velocity on Bowdoin Glacier, Greenland in July 2014

The surface motion of the glacier was measured by surveying 3 stakes (2.0 m long aluminium poles) installed in the ice in the lower part of Bowdoin Glacier. 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 B1401-1403, the antennae were mounted on the stakes and operated every seconds. The stakes at B13T201-B13T204 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 B1401-1403). Measurement errors were estimated below 10 mm.本研究通过对鲍登冰川（Bowdoin Glacier）下游冰体中布设的3根测杆（长2.0米的铝制标杆）开展观测，以获取该冰川的表面运动数据。本次测量采用双频GPS接收机与天线（GNSS GEM-1），采集测杆的三维位置坐标。其中一根天线固定于冰川东岸的基岩之上，作为基准站。针对编号为B1401至B1403的测杆，天线安装于测杆上，以每秒一次的频率进行数据采集。编号为B13T201至B13T204的测杆则采用同一套设备开展了时长30分钟的测量。上述数据通过GPS软件（RTKLIB）以静态解算模式进行处理，以解算测杆的位置坐标；其中B1401至B1403号测杆的坐标每15分钟解算一次。经估算，本次测量的误差小于10毫米。