SNM GeoRadar snow depth

Snow depth is measured using GeoRadar along the SNM transect running in the valley floor of the Zackenberg valley. Measurements are primarily conducted by end of winter, before snow melt is initiated. Positions are given in UTM coordinates (WGS 84, UTM Zone 27 N). Systematic measurements with GeoRadar were implemented in the GeoBasis snow monitoring in 2016. The measured two-way travel time is used to estimate the snow depth by relating this to manual measurements of the snow depth performed along the transect. From linear relationships between the manually measured depths and the travel time, an approximated velocity is found and the snow depth estimated from depth = velocity * one way travel time. For all transects the two way travel time, manual measurements, the approximated velocity and estimated snow depth is recorded alongside the coordinates and information regarding the frequency of the antenna used.本数据集采用地质雷达（GeoRadar），沿扎科本贝克（Zackenberg）山谷谷底的SNM样带开展雪深测量。测量工作主要于冬末融雪启动前完成。测点坐标采用WGS 84椭球下的UTM 27 N坐标系标注。2016年，地质雷达系统测量方案被正式纳入GeoBasis积雪监测体系。通过将实测双向传播时间与沿样带开展的人工雪深测量结果建立关联，可基于该传播时间估算雪深：基于人工实测雪深与传播时间的线性拟合关系，求得近似电磁波速，再通过公式「雪深=波速×单程传播时间」完成雪深估算。所有样带的双向传播时间、人工测量数据、近似波速及估算雪深结果，均与测点坐标及所用天线频率等配套参数一并记录存档。