Kristian Förster, Luisa-Bianca Thiele

Short-term precipitation events with high intensities govern the dynamics of numerous fast hydrological processes like flash floods in urban areas and soil erosion in agriculture. It is expected that precipitation events will intensify as a consequence of climate change. Due to data availability long-term variations in precipitation rates are mostly studied based on daily precipitation recordings while recent research suggests that variations in sub-daily precipitation are subject to higher dynamics compared to daily precipitation and a more rapid intensification is likely. Here we show that both observational data with at least 58 years of sub-daily precipitation records and a minimal dynamical downscaling approach based on atmospheric re-analysis data confirm these expectations with consistent results. High quantiles of precipitation are subjected to multi-decadal oscillations and increased during the last 150 years. For the 2000s we found positive anomalies in high precipitation quantiles relative to the reference period 1850 – 2014 of 6% +/-5% (daily), 13%+/-6% (hourly), and 14%+/-6% (10 min), which is consistent with Clausius-Clapeyron- (CC) and super CC-scaling, respectively. These findings highlight that dynamical downscaling can help to reliably shed light on sub-daily precipitation variations if small timescales are considered in the experiments.