Comparison of simple rain gauge measurements with precision lysimeter data

Standard precipitation measurement techniques are subject to random and systematic errors, affecting the exact determination of precipitation at ground level. The aim of this study was to find a useful and cost-efficient workaround to minimize these errors. For a period of 418 days, precipitation was measured by a tipping bucket rain gauge installed at 1 m height, three Hellmann rain gauges placed on the ground and three lysimeters. Precipitation catch of the lysimeters showed very small deviation (< 0.5%) and was regarded as reference. The tipping bucket at 1 m height caught 12.7% less precipitation. By contrast, ground-level Hellmann gauges caught, on average, similar precipitation as lysimeters. Both methods exhibited large undercatch in wintertime and low undercatch (tipping bucket) or even overcatch (Hellmann gauge) in summertime. Hellmann gauge measurements at ground level allow a fairly exact determination of precipitation for long time periods with low cost and effort.