Standardizing Functional Tests

A standardized test for evaluation of meteorological measuring systems in the natural environment is described. The test is designed to provide a quantitative statistical value that will indicate the reliability of a particular system output. This quantity called functional precision provides a quantitative estimate of the difference in readings that can be expected from systems of identical design and construction when exposed to the same environmental conditions. The mathematical definition of this parameter is described and methods of application are discussed. Two specific examples are presented. A new surface sensor for measuring wind gust is compared with present observational practice and the functional precision determination for an upper air sounding system is summarized.