Comparison of Winter Precipitation Measurements by Six Tretyakov Gauges at the Valdai Experimental Site

Analyses of long-term (1991–2010) intercomparison data quantify the consistency of winter precipitation observations by six identical Tretyakov gauges at the Valdai research station in Russia. Relative to the standard Tretyakov gauge, the mean catch ratios are 97 to 106% for dry snow, 94 to 104% for wet snow, 87 to 109% for blowing snow, 96 to 103% for mixed precipitation, and 98 to 101% for winter rain. The differences between the highest and lowest mean catches are about 10 to 11% for snow, 7% for mixed precipitation, and 3% for rain. On average, this difference is about 0.2?mm over the 12-hour observation period. The catch difference for blowing snow is much higher, up to 22%, or an average of 0.6?mm per observation. Comparisons of 12-hour observations show better consistency in gauge performance for low snowfall events and a large variation in gauge catch for high snowfall events. The differences in 12-hour snow catches are mostly less than 2?mm among the six gauges. The differences in the 12-hour observations are less than 1% for rain and 4% for mixed precipitation. Close linear relationships exist between the 12-hour gauge observations for all precipitation types. The maximum differences in gauge snow catches increase very weakly with wind speed, and higher differences are associated with warmer temperatures, from ?5°C to 0°C. There is, however, no significant relationship between the maximum catch difference and the mean wind speed or temperature over the 12-hour period.