Precipitation-Measurement Intercomparison for NOAA's Historical Climatology Network: The Effects of Wind Shield and Sensor Type

An intercomparison of precipitation sensors and wind shields was performed to help quantify measurement errors and aid in the design of future precipitation measurement systems. Replicates of three different types of weighing gauge, one type of tipping-bucket gauge, and three types of wind shield were installed in an area chosen for its exposure to snow, rain and high-winds. Variability between like measurements was quantified and used to estimate the significance of errors due to shield and sensor type. The largest errors observed were due to inadequate wind shielding during solid-precipitation events, and the magnitude of these errors varied greatly between events. Wind speed and hydrometeor size determine the magnitude of shield-dependent errors, and efforts to model these errors based on easily measured meteorological variables are ongoing.