The GMON3 uses an innovative, non-contact method of measuring snow water equivalency (SWE) for any type of snow or ice. This new sensor offers a reliable alternative to snow pillows and other methods for monitoring SWE. Benefits of the GMON3 include measurements that cover a large surface area (approximately 1000 sq ft) and performance that is unaffected by adverse weather.
The GMON3 monitors gamma rays that are naturally emitted from the ground. An attenuation of the gamma-ray emissions occurs as snow accumulates. Snow with a higher water-content level causes a higher attenuation of the gamma-ray emissions, making it possible to calculate SWE from the gamma-ray measurements.
Snow pillows (a well-established technology for measuring SWE) use a radically different method for determining SWE. Snow pillows consist of bladders filled with antifreeze that is displaced as the weight of the snow accumulates on the bladder. A pressure transducer measures the pressure of this displacement, and from this measurement, SWE is calculated. The GMON3’s method of measuring SWE avoids the hassles of using antifreeze.
In a recent side-by-side comparison, we verified that the GMON3’s measurements are comparable to snow pillow measurements. From December 2009 to April 2010, a GMON3 and a snow pillow monitored SWE at Tony Grove, Utah. As the graph shows, the measurements correlated extremely well.
The GMON3 is manufactured by Campbell Scientific Canada and is collaboration with Hydro Québec where the initial development took place. We look forward to the contributions the new sensor will make to future snow studies.
