Performance characteristics of a new electronic snow water equivalent sensor in different climates

The US Army ERDC CRREL and the US Department of Agriculture Natural Resources Conservation Service developed a square electronic snow water equivalent (e-SWE) sensor as an alternative to using fluid-filled snow pillows to measure SWE. The sensors consist of a centre panel to measure SWE and eight outer panels to buffer edge stress concentrations. Seven 3m square e-SWE sensors were installed in five different climate zones. During the 2011-2012 winter, 1.8 and 1.2m square e-SWE sensors were installed and operated in Oregon. With the exception of New York State and Newfoundland, the e-SWE sensors accurately measured SWE, with R-2 values between the sensor and manual SWE measurements of between 0.86 and 0.98. The e-SWE sensor at Hogg Pass, Oregon, accurately measured SWE during the past 8years of operations. In the thin, icy snow of New York during midwinter 2008-2009, the e-SWE sensors overmeasured SWE because of edge stress concentrations associated with strong icy layers and a shallow snow cover. The New York e-SWE sensors' measurement accuracy improved in spring 2009 and further improved during the 2011-2012 winter with operating experience. At Santiam Junction, measured SWE from the 1.8 and 1.2m square e-SWE sensors agreed well with the snow pillow, 3m square e-SWE sensor, and manual SWE measurements until February 2013, when dust and gravel blew onto the testing area resulting in anomalous measurements. (c) 2014 The Authors. Hydrological Processes published by John Wiley & Sons Ltd.