Performance Analysis of GMON3 Snow Water Equivalency Sensor

TitlePerformance Analysis of GMON3 Snow Water Equivalency Sensor
Publication TypeConference Proceedings
Year of Conference2011
AuthorsWright, M., Kavanaugh J., and Labine C.
Conference Name79th Annual Western Snow Conference
Series TitleProceedings of the 79th Annual Western Snow Conference
Date PublishedApril 2011
PublisherWestern Snow Conference
Conference LocationStateline, NV
KeywordsAlberta, snow water equivalent, SWE, GMON3, snow pillow, precipitation gauge, snow course, SNOTEL

This report evaluates the performance of the GMON3 Snow Water Equivalency (SWE) sensor developed by Hydro Québec in collaboration with Campbell Scientific Canada Corporation. The GMON3 determines SWE by measuring the attenuation by the snowpack of naturally emitted terrestrial gamma radiation from the soil. This provides a non-contact technique for determining SWE that is effective with any type of snow or ice cover and whose performance is not affected by adverse weather conditions. Field testing of the GMON3 was carried out at Sunshine Village, Alberta from 2008-2011 and at the SNOTEL Tony Grove Ranger Station, Utah from 2009-2010. The GMON3 values were compared to other sensors, which produce SWE either directly or indirectly: snow pillow, precipitation gauge, snow depth sensor, and manual SWE values from snow course measurements. Strong agreement is shown both qualitatively and quantitatively between all automated methods of SWE: GMON3, snow pillow, and precipitation gauge. Statistically, all automated methods show correlations of 0.99 over the entire season and up to peak periods. Monthly snow course measurements were found to be the least reliable method for measuring SWE. Analysis of the GMON3 suggests that it provides comparable, if not better, SWE accuracy to the snow pillow and precipitation gauge, while eliminating the disadvantages associated with both of these techniques.