Sampling Errors of Tipping-Bucket Rain Gauge Measurements

Abstract

In this study we investigated sampling-related errors of tipping-bucket (TB) rain gauge measure- ments, focusing on the gauge’s ability to represent the small-scale rainfall temporal variability. We employed a simple TB simulator that used ultra-high-resolution measurements from an experimental optical rain gauge. The simulated observations were used to provide TB rain rate estimates on time scales as low as one minute. The simulation results showed that the TB estimates suffer from significant errors if based on time scales less than 10 to 15 minutes. We provide the approximate formulas used to characterize the TB sampling errors at several time scales. Our results show the importance of using fine resolution of both the sampling time interval and the bucket size so that the TB rain rate estimates have minimum levels of uncertainty.