Performance of Hot Plate for Measuring Solid Precipitation in Complex Terrain during the 2010 Vancouver Winter Olympics

Abstract

olid precipitation intensity, snow density, wind speed, and temperature were collected from November 2009 to February 2010 at a naturally sheltered station located at an altitude of 1640 m MSL on Whistler Mountain in British Colombia, Canada. The snowfall was measured using the instruments OTT Pluvio; the Yankee Environmental Systems, Inc., hot plate (HP); and the Vaisala FD12P (optical weather sensor). The snow amount and density were also measured manually daily. The observed wind speeds were in the range 0?4.5 m s?1 with a mean value of 0.5 m s?1. Based on this study, the HP overestimated the snow amount by about a factor of 2 as compared to the Pluvio measurements. Further data analysis using the raw output HP data suggests that this was because of false precipitations produced, particularly by the downslope flows in the complex terrain when the wind speeds were relatively stronger. This false precipitation varied from ?0.9 to 1.3 mm h?1 with two peaks at 0.1 and 0.3 mm h?1 depending on wind speed?the larger peak being at higher wind speeds. Since the observed wind speeds were relatively calm, setting the correction factor to 0.15 mm h?1 gave reasonable values as compared to the Pluvio data. The difference between the corrected HP and Pluvio accumulation data varied from 16% to 3% depending on wind speed. The observed snow density in January 2010 varied from 0.04 to 0.32 g cm?3 with a mean value of 0.08 g cm?3. The snow amount measured using the corrected HP data agreed well with the manually measured values with a correlation coefficient of 0.93.