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On pulsed Doppler radar measurements of avalanches and their implication to avalanche dynamics
AbstractPulsed Doppler radar measurements from several avalanche releases are analyzed to gain an in-depth understanding of avalanche dynamics. A pulsed Doppler radar emits short pulses and samples the echo in distinct time intervals, corresponding to distance intervals (range gates). Frequency analysis of the echo signals, exploiting the Doppler-effect, yields the velocity distribution within the width of a range gate. Thus, it is possible to gain information on the front speed along the track and information on the velocity versus time at a specific location along the track.In addition to the avalanche velocity, information on the magnitude of accelerations/decelerations along the track can be derived. To this end, the velocities of a pair of adjoining range gates are compared. The acceleration/deceleration values can give hints to parameters in the friction terms of commonly used numerical avalanche models. The derived retarding accelerations imply a behavior different to the one proposed in those models. They also indicate a dependency of the retarding acceleration on the stage of the flow.
On pulsed Doppler radar measurements of avalanches and their implication to avalanche dynamics
AbstractPulsed Doppler radar measurements from several avalanche releases are analyzed to gain an in-depth understanding of avalanche dynamics. A pulsed Doppler radar emits short pulses and samples the echo in distinct time intervals, corresponding to distance intervals (range gates). Frequency analysis of the echo signals, exploiting the Doppler-effect, yields the velocity distribution within the width of a range gate. Thus, it is possible to gain information on the front speed along the track and information on the velocity versus time at a specific location along the track.In addition to the avalanche velocity, information on the magnitude of accelerations/decelerations along the track can be derived. To this end, the velocities of a pair of adjoining range gates are compared. The acceleration/deceleration values can give hints to parameters in the friction terms of commonly used numerical avalanche models. The derived retarding accelerations imply a behavior different to the one proposed in those models. They also indicate a dependency of the retarding acceleration on the stage of the flow.
On pulsed Doppler radar measurements of avalanches and their implication to avalanche dynamics
Gauer, Peter (author) / Kern, Martin (author) / Kristensen, Krister (author) / Lied, Karstein (author) / Rammer, Lambert (author) / Schreiber, Helmut (author)
Cold Regions, Science and Technology ; 50 ; 55-71
2007-03-21
17 pages
Article (Journal)
Electronic Resource
English
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