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

Abstract

Solid 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 21 with a mean value of 0.5 m s 21 . 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 20.9 to 1.3 mm h 21 with two peaks at 0.1 and 0.3 mm h 21 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 21 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 23 with a mean value of 0.08 g cm 23 . The snow amount measured using the corrected HP data agreed well with the manually measured values with a correlation coefficient of 0.93.

Meteorological Knowledge Useful for the Improvement of Snow Rain Separation in Surface Based Models

“…Many of the automated methods/instruments that report precipitation phase use; (1) Doppler radar; (2) optical sensors [66]; (3) hotplates [67] or (4) two dimensional video distrometers (2DVD) [68]. However, they have often been put into operation without an in-depth intercomparison which brings into question the quality, consistency, compatibility, and representativeness of their data [66].…”

Hotplate precipitation gauge calibrations and field measurements

“…This work furthers efforts to advance the hotplate as a snowfall measurement system (Borkhuu, 2009;R11;Boudala et al, 2014). We develop calibration constants for two hotplate systems configured with longwave and shortwave radiation sensors.…”

“…We surmise that the difference comes from the following: (1) R11's assignment of A h (0.00884 m 2 vs. 0.01327 m 2 in the UW algorithm), (2) R11's distinction between a theoretical and an actual energy conversion factor, and (3) the incorporation of points 1 and 2 into the YES algorithm. Clearly, R11's A h is not justified for hotplates sold by YES (Boudala et al, 2014;YES, personal communication, 2017). R11's distinction between conversion factors is more problematic.…”

“…We do not find justification for this in R11, nor do we agree with R11's assignment of A h = 0.008844 m 2 , assuming they were recommending that value for the hotplate sold by YES. Recently, Boudala et al (2014) addressed the second of these two points, making it clear that A h = 0.01327 m 2 is appropriate for the hotplate sold by YES.…”

Case Studies of Low‐Visibility Forecasting in Falling Snow With WRF Model

“…It should be noted that the accuracy of snowfall measurements can be affected by wind speed, depending on the kind of snow gauge being used. In fact, the wind always induces undercatch of solid precipitation (Boudala, Isaac, et al, ; Boudala, Rasmussen, et al, ; Førland et al, ; Goodison et al, ; Rasmussen et al, , ; Thériault et al, ; Yang et al, ; Wolff et al, ). For example, Boudala et al () found that the single Alter Pluvio2 automatic catchment‐type gauge caught approximately 85% of the true snowfall amount at 2 m s −1 as compared to about 40% at 5 m s −1 .…”