An enhanced technique for a more reliable daily snow measurements with an antifreeze-based tipping bucket gauge

The record snowfall during the 1996-1997 winter season and subsequent spring flood stressed the need for a suitable method to measure daily snowfall at all 52 North Dakota Agricultural Weather Network (NDAWN) stations. Our goal was to obtain accurate daily winter precipitation values from a remote automatic weather station. In November 1997, a system comprised of a Texas Electronics TE5253 rain gauge with a Campbell Scientific CS705 antifreeze based snow adapter, suitable for obtaining a reasonable estimate of the total seasonal precipitation (McCaughey and Fames, 1996), was installed at Fargo, North Dakota NDAWN station. Laboratory testing identified an antifreeze overflow restriction and a system support problem. We redesigned the shape of the overflow tube and added surfactant to the antifreeze mixture to diminish surface tension. We installed a weight support (tripod) and a side post to increase gauge stability in windy conditions and maintain a plumb position. The new system was tested during the second half of the 1997-98 winter, and the 1998-99 and 1999-2000 v.inter seasons. Comparative data for each snow precipitation event were recorded, collected and analyzed from three different sources: NWS Coop observer located about two miles E, a standard NWS universal Belfort weighing gauge, and the adjacent TE525/CS705 tipping bucket gauge/snow adapter at the Fargo, NDAWN station. The combination of the new overflow tube design, added surfactant and a reliable support system, enhanced the flow timing and provided more reliable daily totals.