Snow depth_EmpSa_PitTransect

Snow depths are measured in cross transects at each cores site of the snow survey using RTK GPS. The ground surface of the EmpSa transects was measured in 2012, and a two-dimensional digital elevation model of the terrain along each transect was extracted. During the snow survey, the snow surface along the transects is measured, and snow depth is calculated by projecting it onto the terrain model. In order to achieve a precise geographical reference, the section nodes for all the repeatable transects have been established with a Leica 1200 RTK GPS. The GPS rover receives corrections from a GPS base station placed on the reference point ‘Kobbefjordfix’, which consists of a bolt anchored in rock. Using the RTK GPS rover and base station allows the horizontal and vertical position to be determined within 3 and 5 cm, respectively.本积雪调查在各岩芯采样点位处，通过布设横断面样线开展雪深测量，测量工作依托实时动态GPS（RTK GPS）完成。2012年已完成EmpSa样线的地表高程测量，并提取得到每条样线沿线地形的二维数字高程模型。本次积雪调查期间，对各条样线沿线的积雪表面进行高程测量，再通过将积雪表面高程投影至前述地形模型的方式计算雪深。为获得精确的地理参考基准，所有可重复样线的断面节点均通过徕卡1200 RTK GPS进行定位布设。GPS流动站接收设于参考点'Kobbefjordfix'的GPS基准站发来的差分修正信号，该参考点由锚固于岩石中的螺栓构成。依托这套RTK GPS流动站与基准站系统，可实现水平位置与垂直位置的测量精度分别控制在3厘米与5厘米以内。