S152 Investigating the sources of inaccuracy in a Geonor precipitation gauge

Sunday, 22 January 2017
4E (Washington State Convention Center )
Keon Gibson, UCAR/NCAR, Boulder, CO; and S. Landolt

This study describes various techniques for correcting the data output from the Geonor T-200B Precipitation Gauge, which utilizes vibrating wire technology to measure the accumulating mass of precipitation. In some instances, data recorded by the gauge is unusually noisy. This study aimed to isolate the source of the noise in the vibrating wires’ frequency data by isolating variables that may be causing the problem. The goal was to recommend ways to modify the instrument to produce more accurate precipitation data. To study the vibrating wires, a 326-gram weight was placed the wires in a test enclosure to see how they performed with a static load in isolation. This test showed that wire two was noisier than the others. During the day, changes in the wire frequencies were associated with the changing ambient temperatures. Plots showed a strong correlation between ambient temperature and the data being recorded by the precipitation gauge. There are additional sources of noise, one of which was revealed after a power outage occurred during this test; the noise on wire two diminished, wire three began producing more noise, and the output from wire one did not change. This showed that many factors may be contributing to the inaccuracy of the frequency outputs the gauges produce. Engineers and other researchers can use this information to further improve the accuracy of this instrument.
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