Estimating Alter-shielded gauge snowfall undercatch, snowpack sublimation, and blowing snow transport at six sites in the coterminous USA

Computing the monthly and winter water balance for cold regions can be difficult due to data scarcity. Historically, the spatial resolution, temporal resolution, and the number of variables measured have been limited. Currently, these data are once again becoming limited. To estimate the net snowpack accumulation, measured precipitation must be adjusted to consider precipitation underestimation due to gauge undercatch, the snow lost to sublimation, and blowing snow transport. Using existing formulations, hourly meteorological data were used to estimate snowpack sublimation and blowing snow transport losses for three winters at six National Weather Service (NWS) automated surface observation stations across the coterminous USA. Wind-induced undercatch was estimated from daily data for the collocated NWS Alter-shielded gauges. For the average wind speed sites (the average wind speed was from 2.4 to 4.3 m s(-1)), 70% of the snow that fell was caught, whereas at the low wind site (1.3 m s(-1)), 90% was caught and only 46% was caught at the high wind site (5.6 m s(-1)). Average snowpack sublimation ranged from 7 mm per month at either low wind or low precipitation sites to over 20 mm per month at average wind sites with either average precipitation and low humidity or high precipitation and moderate humidity. Blowing snow transport was only important at higher wind sites (>4 m s(-1)). A distinct relationship was not obvious for average monthly meteorology for undercatch versus snowpack sublimation plus blowing snow losses. Seasonally, they are approximately equal for more snowy and wet environments. Copyright (C) 2004 John Wiley Sons, Ltd.