upRADAR - Monitoring of temporal changes within the snowpack utilizing upward-looking radar technology

Achim.Heilig [ at ] awi.de


Previous snowpack monitoring systems deployed for the entire winter season are either limited to the information of the snow height or weight at a specific point or are inadequate in monitoring the temporal evolution of the snowpack as the method is destructive. Due to an expected spatial variability in the snowpack stratigraphy, only non-destructive sensor systems are suited to observe the temporal evolution of the snowpack, e.g. strain rates of specific layers after recent snow loading or the observation of the penetration of wetting fronts until liquid water percolated all the way down to the ground. For this study, two different upward-looking radar systems buried into the ground provid an extensive data set of the temporal changes in snowpack stratigraphy and characteristics. The radars recorded data for almost five months every three hours in dry-snow conditions and down to every 30 minutes, while moisture occurred in the snowpack. In comparison to a previously employed and tested upward-looking impulse radar system (upGPR), a distinctive less cost-intensive self-made frequency modulated continuous wave system (upFMCW) in a similar frequency range was tested on its applicability. The scope of this paper is to compare the radar signals gathered with two different frequencies (600, 1600 MHz) by the upGPR with signals recorded by the upFMCW in the frequency range of 1-2 GHz. In combination with conventional snowpack measurements, both radar data demonstrate applicability to validating and improving snowpack models The method seems to provide an unique possibility to determine the differential volumetric liquid-water content (\theta_{W}) in the snowpack and monitor sub-daily to monthly changes thereof. The occurrence of strong multiple reflections as well as the diurnal increase in two-way travel time of reflection horizons effected by moisture allow to determine the absolute amount of \theta_{W}, the depth of moisture percolation, the timing of the diurnal peak and the monitoring of the decrease in \theta_{W} due to nocturnal refreezing.

Item Type
Conference (Invited talk)
Publication Status
Event Details
AGU American Geophysical Union - fall meeting, 05 Dec 2011 - 09 Dec 2011, San Francisco.
Eprint ID
Cite as
Heilig, A. , Schmid, L. , Mitterer, C. , Eisen, O. , Schweizer, J. and Okorn, R. (2011): upRADAR - Monitoring of temporal changes within the snowpack utilizing upward-looking radar technology , AGU American Geophysical Union - fall meeting, San Francisco, 5 December 2011 - 9 December 2011 .


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