87th AMS Annual Meeting

Wednesday, 17 January 2007: 4:00 PM
Ultrasonic snow depth sensors for National Weather Service (NWS) snow measurements in the U.S.: Evaluation of operational readiness
207A (Henry B. Gonzalez Convention Center)
Wendy A. Ryan, Colorado State University, Fort Collins, CO; and N. J. Doesken
Poster PDF (404.9 kB)
This presentation will provide a description of plans and preliminary results of the 2006-2007 National Weather Service operational readiness evaluation of ultrasonic snow depth sensors. Three depth sensors are being installed in a triangular plot at 16 NWS weather forecast offices across the U.S including Alaska. Automated data from this array of sensors will be compared to traditional 6-hour and daily manual measurements of snowfall, depth and water equivalent. There is great interest in automating snow observations in order to track snow accumulation in near real-time without the need for trained observers for various applications such as weather forecasting and verification, flood warning systems, transportation applications and public information. Depth sensors have been available commercially for several years, but are just now being considered for use in operational weather and climate observing systems. Estimating snowfall from continuous readings of total depth requires considerable understanding of snowpack characteristics such as settling, melting, and redistribution. While the technology has excellent potential, there are a number of climate data continuity issues related to changing data collection methodologies that this program will be addressing. For example, changing frequency of observations and moving from spatial averaging (which trained observers do when snow accumulation is irregular) to point measurements could introduce biases. However, there are already known variations and inconsistencies in manual observations that have always plagued snowfall data, and automation may reduce some observational inconsistencies. This project is being conducted in collaboration with Environment Canada (EC) with the hopes of standardizing snow measurements across our borders.

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