Aerodynamic roughness length of crevassed tidewater glaciers from UAV mapping in Svalbard

This dataset contains of aerodynamic roughness length (z0) estimations of four glaciers in Svalbard. The data was generated in the scope of a project between NTNU, UNIS, and ETH Zürich. The aerodynamic roughness length z0 is an important parameter in the bulk approach for calculating turbulent fluxes and their contribution to ice melt. However ,z0 estimates for heavily crevassed tidewater glaciers are rare or only generalized. This study used unmanned aerial vehicles (UAVs) to map inaccessible tidewater glacier front areas. The high-resolution images were utilized in a structure-from-motion photogrammetry approach to build digital elevation models (DEMs). These DEMs were applied to five models (split across transect and raster methods) to estimate z0 values of the mapped area. The results point out that the range of z0 values across a crevassed glacier is large, with up to three orders of magnitude. The division of the mapped area into sub-grids (50m x 50m), each producing one z0 value, accounts for the high spatial variability of z0 across the glacier. The code can be accessed via https://github.com/ArminDach/z0_UAVs/

本数据集收录了斯瓦尔巴群岛四座冰川的空气动力学粗糙度长度（z0）估算值。该数据生成于挪威特罗姆瑟科技大学（NTNU）、挪威大学（UNIS）与苏黎世联邦理工学院（ETH Zürich）之间的合作项目框架内。空气动力学粗糙度长度z0是计算湍流通量及其对冰融贡献的混合方法中的重要参数。然而，对于深度裂隙的潮汐冰川，z0的估算数据极为罕见或仅作一般化处理。本研究利用无人机（UAV）对难以到达的潮汐冰川前沿区域进行测绘。高分辨率图像被应用于结构从运动摄影测量法，以构建数字高程模型（DEM）。这些DEM应用于五种模型（分布在不同横切线和栅格方法中），以估算测绘区域的z0值。研究结果指出，裂隙冰川上z0值的变化范围较大，可达三个数量级。将测绘区域划分为子网格（50米×50米），每个子网格生成一个z0值，这解释了冰川上z0值的高空间变异性。相关代码可通过https://github.com/ArminDach/z0_UAVs/获取。