Metrological analysis of a gravimetric calibration system for tipping-bucket rain gauges

The monitoring of hydro-meteorological variables for operational and research purposes requires accurate measurements. The reliability of such measurements varies depending on the need to meet different requirements in several sectors, including aviation, agriculture, civil protection, entertainment and weather forecast. In the case of rain gauges, many factors and variables affect themeasurement of liquid and solid precipitation in the field. Calibration is a primary tool for quality control and requires suitable infrastructure to perform the tests, and is done by using properly evaluated testing methods and procedures. The current study presents the analysis of a typical calibration system for tipping-bucket rain gauges, using the gravimetric method, in accordance with the recommendations and requirements of both meteorology and metrology. As a result, the uncertainty contribution of each component of the system and an assessment of the resulting overall uncertainty budget are obtained.