Operational Techniques for Determining SWE by Sound Propagation through Snow

• Main Authors: Eastern Snow Conference Lake, Morley
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Published: 2008
• Subjects: Canada; Yukon; Tundra; Whitehorse
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.1084.7207; http://www.usask.ca/ip3/download/publications/ESC2008_KinarPomeroy.pdf

ABSTRACT Recent research has demonstrated that an acoustic pressure wave can be used to determine snow water equivalent (SWE) without the need for gravimetric sampling. The application of this technique poses a number of challenges in cold environments due to the presence of snow with wind crusts, ice layers, buried vegetation and high liquid water content and due to the extensive signal processing required after collection of returned sound waves. To show that the technique can contribute to operational SWE surveys, portable, field-usable devices were constructed with the capability of reliable on-line signal processing and calculation of SWE in the field. Reflections of the sound wave from the snowpack were identified by a peak detector algorithm and then analyzed. The acoustic method, portable field devices and modified signal processing techniques were tested at forest and tundra sites near Whitehorse, Yukon Territory, and at forest and meadow sites in the Rocky Mountains, Alberta, Canada. Comparisons were made between the acoustic technique and gravimetric sampling conducted using snowpits and density samples of individual snow layers and with bulk gravimetric sampling using an ESC30 "snow tube" snow density sampler and ruler. These comparisons demonstrated that the acoustic measurement with the portable field unit and on-line modified signal processing technique can provide SWE estimates in the field that are of comparable accuracy to SWE calculated from gravimetric samples. The on-line processing allows the operator to gauge the reliability of the measurement and to ensure sufficient data collection before leaving the field site. Significant advantages over gravimetric sampling accrue from non-destructive sampling of the snowpack and easy of measurement. Limitations and aspects for further research are also discussed.