Brief Communication: Evaluating Snow Depth Measurements from Ground-Penetrating Radar and Airborne Lidar in Boreal Forest and Tundra Environments during the NASA SnowEx 2023 Campaign

We evaluated ground-penetrating radar (GPR) and airborne lidar retrievals of snow depth collected during the NASA SnowEx 2023 campaign in Alaskan tundra and boreal forest environments along 44 short (3–12 m) transects. Compared to in situ observations, we identified modest biases for GPR snow depths (bias <0.03 m in tundra, +0.06 m in boreal forests) and larger biases for lidar snow depths (bias +0.19 m at a tundra site, –0.16 m in boreal forests) related sub-snow vegetation, tussocks, and seasonally dynamic ground. These complex surface environments present a challenge to established methods, which needs to be considered when evaluating novel remote sensing approaches.