Two-way Travel Time (TWTT) In Snowpack, Derived from Software-defined Radar Data Collected by Small, Uncrewed Aircraft Systems (sUAS) in Colorado, 2022-25.

These datasets were collected by a ground penetrating radar unit installed on small Uncrewed Aircraft Systems (sUAS). Data include the two-way travel time (TWTT) for the ground surface (distance between the snow-ground interface and sUAS) and the calculated snow depth. The snow depth TWTT is defined as the time duration in nanoseconds that the electromagnetic wave takes to travel from the air-snow interface, reflect from the snow-ground surface, and then reach the air-snow interface again. The snow-ground and snow-air interfaces were identified by the magnitude of returns through a surface detection algorithm. The TWTT value provided in the dataset is a function of the snow depth and the radar wave velocity in the snow, which can be calculated from the snowpack density and the volumetric liquid water content in the snowpack. The sUAS based Software-defined Radar (SDRadar) data were collected during the snow-on-field campaigns in tandem with manual discrete snowpack measurements at Berthoud and Coal Bank Passes in Colorado, 2022-25. More information regarding the sUAS system used and data collection methods can be found in each metadata file Supplemental Information section for each data collection effort.