Evaluation of the effectiveness of precipitation gauge wind shielding for real-time snow measurement

Adequate wind shielding is a crucial part of measuring liquid equivalent snowfall, especially when trying to measure snowfall in real-time. Real-time snowfall estimates are crucial to ground de-icing operations because it has been determined that de-icing fluid failure time is inversely proportional to the liquid water equivalent amount in snow. There are dozens of wind shield designs from around the world, each with its own design and performance characteristics. NCAR has been evaluating several wind shields at our NCAR/Marshall instrument test site over the past six years. An experiment was conducted in which we placed identical Geonor T-200 precipitation gauges in a variety of wind shields. In order to better understand the performance of the various wind shields we also measured the wind flow around and inside the various wind shields. Data was collected from a winter season of snow events and the NCAR/Marshall site in Boulder, CO. In this paper we report on results of this experiment and quantify the relative effectiveness of the various wind shields in snow conditions.