Match Analysis and Simulation Verification of Throughfall Collector and Tipping Bucket Rain Gauges

In this study, 2 types of tipping-bucket rain gauges with resolutions of 0.5 mm and 1.0 m, raindrop collectors with 3 different area sizes, and 5 simulated throughfall intensities were employed. Additionally, the speed-flow regression equation of the peristaltic pump was developed to replicate penetrating throughfall at different intensities. The results demonstrated that the collector with the size of 200 mm × 392.5 mm was equipped with 0.5 mm and 1.0 mm resolution rain gauges, both of which can achieve accurate single point observation, but the area was small and the representation of single point was poor. The size of 200 mm × 785 mm was equipped with the rain gauge of 0.5 mm, which could only observe the throughfall below 1.0 mm/min accurately. With a rain gauge of 1.0 mm, which could be observed within the range of intensities from 0.0 mm/min to 3.0 mm/min, but error correction was required for throughfall stronger than 2.0 mm/min. The size of 200 mm × 1570 mm was equipped with the rain gauge of 1.0 mm, which could be observed normally under the intensities from 0.0 mm/min to 2.0 mm/min, the error correction should be carried out for the intensities from 1.0 mm/min to 3.0 mm/min. Based on comprehensive analysis, the collector measuring 200 mm × 1570 mm and equipped with a rain gauge of 1.0 mm demonstrated the highest level of accuracy for single point representation while meeting observation requirements and remaining cost-effective, thus making it the most suitable configuration. If flow meters with larger tipper volumes customized, observation stability and accuracy of throughfall will be further improved.