Using liquid-equivalent snow gauge measurements to determine snow depth-Preliminary Results
Kevin Van Galloway, NCAR, Boulder, CO; and S. D. Landolt and R. M. Rasmussen
The capability of liquid equivalent snow gauges to use multiple sensors to estimate snow depth is analyzed. Algorithms using measurements from existing sensors, including a liquid equivalent snow gauge, are used to determine expected snow depth and whether an ultrasonic depth sensor is necessary for reporting existing snow depths. Current ultrasonic depth sensors (USDS) measurements are affected by a variety of factors including snow crystal type, intense snowfall, wind speed, uneven snow surfaces, extreme temperatures, and the presence of blowing or drifting snow. These factors restrict the applicability of USDS to specific sites such as sites shielded from wind and extreme temperatures. Multiple existing equations for determining snow depth are analyzed to determine the best method for estimating snow depth indirectly. The effects of changing snow density, wind speeds, and compaction from metamorphosis and overburden on snow depth are included in the snow depth algorithm. Quality assurance and quality control of data are included in the algorithm to eliminate variability in snow depth reports that is commonly associated with the use of USDS. The goal of this study is to develop an algorithm that uses existing sensor measurements of liquid equivalent, temperature, wind speed, precipitation type, and precipitation amounts to report an accurate real time estimate of snow depth. In doing so, comparisons are made with the Judd and Campbell USDS to determine whether the addition of these sensors to existing instrumentation is necessary, and whether a more accurate and robust method is available for reporting snow depth.
Extended Abstract (1.4M)
Session 1, Hydrological Measurements
Monday, 15 January 2007, 4:00 PM-5:30 PM, 207A
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