Intercomparison of measurements at climate reference stations in Germany on the influence of funnel heating of a precipitation device

Abstract. Accurate and reliable long time series of precipitation data are essential for a variety of applications and for accurate quantification of climate change. Such time series should be as homogeneous as possible, but certain changes in measurement conditions cannot be avoided. Parallel measurements are carried out at the German climate reference stations to analyse the effects of changes in the measurement systems, e.g. changing one measuring instrument to another. The aim of these parallel measurements is to identify measurement uncertainties and to analyse the comparability of the measurement systems in order to investigate homogeneity. In this study, the influence of funnel heating on precipitation measurement was analysed using the rain[e] device. General analyses show that the rain[e] sensor measures more precipitation than the PLUVIO sensor, for liquid precipitation regardless of the amount of precipitation. But for solid precipitation PLUVIO measures more. Differences in the equipment of the devices, such as heaters, could cause the measurement differences. An investigation during winter of 2023/2024 showed that changing the funnel heater temperature setting in the rain[e] influences the amount of precipitation measured. A change in the funnel temperature by 2 °C changed the amount of precipitation by approx. 1.5 %.