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/