Radar-Rainfall Data: A Storm of Solutions or a Pool of Problems?

The concept of using radar to augment rain gauge measurements between gauges first appeared at WEF (WPCF) in 1992. The industry has grown considerably since then as has the notion that radar-rain (gauge adjusted radar) calculations are almost immaculate and should be accepted as the best estimate of real rainfall that there is. The paper show examples of gauge adjusted radar that were quite poor and that should not have been used for engineering purposes. The paper proposes a series of four statistical tests that can be applied to gauge adjusted radar results to determine the validity of the data. The paper also provides a set of performance standards for gauge adjusted radar that can be placed in an RFP to help guaranty that users pay only for good data. Finally, the paper offers the statistical radar-rainfall database to any user who needs to evaluate the validity of gauge adjusted radar result.