Improvement of Rainfall Measurements by Using a Dual Tipping Bucket Rain Gauge

The Dual Tipping Bucket Gauge (DTBG) is newly developed to improve the accuracy of rainfall measurements. DTBG includes two tipping buckets (TBs) in a gauge cylinder, named TB01 and TB05. The measurement resolution of TB01 and TB05 are 0.1 mm and 0.5 mm, respectively. Rainfall measurements by DTBG are made simultaneously by the two TBs. The higher amount of rainfall from either TB01 or TB05 is then taken as the rainfall amount by DTBG, which constitutes a major advantage of DTBG compared to a single TB rain gauge. For 14 rainfall events, the accuracy of DTBG was assessed by inter-comparisons of rainfall amounts by DTBG and Pluvio2 (reference gauge). The rainfall intensities by DTBG were fairly consistent with those by Pluvio2, with an average fractional bias of 0.07%. The present study demonstrates that DTBG is more accurate and reliable compared to a single TB rain gauge.