Harcourt, William D. and Robertson, Duncan A. and Macfarlane, David G. and Rea, Brice R. and James, Mike R. and Diggins, Mark and Fyffe, Blair (2025) Spatial and temporal variations in 94 GHz radar backscatter from a springtime snowpack. IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing, 18. pp. 3611-3624. ISSN 1939-1404
Full text not available from this repository.Abstract
Terrestrial snow cover is a perennial feature of the mountain cryosphere and can change rapidly in response to variable weather patterns. Measuring the interaction between atmospheric conditions and a snowpack at high spatial and temporal resolution requires the use of close-range sensors. Here, we measured the variability of a spring snowpack across two corries in Scotland using ground-based 94 GHz radar in order to assess its ability to monitor snowpack changes. We deployed both the 2 nd generation All-weather Volcano Topography Imaging Sensor (AVTIS2) 94 GHz radar and a Riegl LPM-321 Terrestrial Laser Scanner (TLS) in the Cairngorms National Park, Scotland, in March 2021 over 3 days. AVTIS2 is a tripod-mounted, real-aperture radar system which mechanically scans across a scene of interest to map normalised radar cross section (σ0) and 3D point clouds. We measured an increase in σ0 of ∼ 10 dB over 24 hours during which time the daytime (09:00-18:00) average air temperature reduced from 2.2°C to 0.3°C. We suggest this increase in radar backscatter was due to the transition of the snowpack from surface melting to a refrozen state. Overnight, snow drift led to the formation of windslab across the headwall of the corrie and subsequent snowpack failure, which we identified through a localised increase in σ0 of 10-15 dB. The high sensitivity of 94 GHz radar backscatter to changes in snow surface conditions demonstrates the capabilities of millimetre-wave radar for daily monitoring of snow cover characteristics across complex topography with a spatial resolution of approximately a few metres.