Season-long non-destructive monitoring of snowpack surface and internal dynamics using terrestrial LiDAR and GPR

Snowpack evolution in cold-region environments is governed by complex interactions between surface energy exchanges and internal stratigraphic processes that vary throughout the winter season. Capturing these dynamics at high temporal resolution remains challenging with conventional point-based or destructive methods. This study presents a season-long, predominantly non-destructive monitoring approach combining fixed-station terrestrial LiDAR and high-frequency ground-penetrating radar (GPR) to observe snowpack surface and internal dynamics across multiple winter processes.

Field measurements were conducted throughout the winter at two contrasting eastern Canadian watersheds. Sainte-Marthe (45°N) is a lowland agricultural catchment (110 m a.s.l.) with shallow, ephemeral snow cover, while the Montmorency Forest (47.3°N) is a boreal watershed (670 m a.s.l.) characterized by a deep, persistent snowpack. GPR systems operating at 1500 MHz and 500 MHz were deployed at Sainte-Marthe and Montmorency, respectively, to account for contrasting snow depths. A fixed 905 nm fixed LiDAR system operated concurrently at both sites, providing hourly measurements of snow surface elevation and properties. Manual snowpit surveys, including density and A2 permittivity measurements, were performed throughout the winter to constrain electromagnetic wave velocity and support GPR inversion.

LiDAR observations capture continuous changes in snow surface state, including accumulation, compaction, melt, deformation, and surface roughness, revealing periods of enhanced energy input at the snow–atmosphere interface. Corresponding variations in GPR signal amplitude, two-way travel time (TWT), and frequency content indicate internal stratigraphic adjustments within the upper snowpack layers.

Overall, integrating LiDAR and GPR with traditional monitoring stations demonstrates strong complementarity for continuous, non-destructive monitoring of snowpack processes over an entire winter season, providing new observational constraints relevant to cold-region hydrological and cryospheric modelling