Revealing the structure of precipitation extremes: a spatio-temporal wavelet approach

Abstract. The impact of a heavy precipitation event is determined not only by the total amount of precipitation, but also by its spatial and temporal distribution. This study introduces a framework to quantify the key spatio-temporal properties of precipitation events - namely their characteristic time, length and speed - using radar-based observations. We employ a spectral filtering approach based on wavelet decomposition, which allows the selective extraction of precipitation signals at distinct temporal and spatial scales.

Focusing on Germany, we analyze the 100 most extreme two-day summer precipitation events using the high-resolution RadKlim dataset provided by the German Weather Service. We evaluate the physical plausibility of the derived characteristics and investigate their relationships with large-scale atmospheric dynamics. Our results reveal systematic patterns in the spatio-temporal organization of precipitation extremes. The framework presented here provides a robust tool for understanding extreme precipitation and offers potential for improved risk assessment and future climate studies.