Regional frequency analysis of maximum 2-day precipitation in Slovakia

Ongoing climate change continues to accelerate, significantly altering climatic conditions across the globe. These changes are evident not only in the rising mean global temperature but also in the increasing frequency and intensity of extreme weather events (IPCC, 2021). Extreme precipitation events, characterized by high multi-day precipitation totals, pose a severe risk to infrastructure, public safety, and property, even in the absence of climate change. This study presents a comprehensive seasonal regional frequency analysis (RFA) of maximum 2-day precipitation totals (Rx2D) in Slovakia using the L-moment approach (Hosking and Wallis, 1997). We analyzed 70 years (1951–2020) of precipitation data from 419 stations. The stations were grouped into homogeneous regions using a multi-regression approach and distance matrices, enabling the development of regional frequency curves. The L-moments ratio diagrams, 𝑍𝐷𝑖𝑠𝑡 measure, and Anderson-Darling goodness-of-fit tests were applied to identify the most suitable theoretical extreme-value distributions. The analysis identified nine distinct regions, with the generalized extreme value (GEV) distribution providing the best fit for Rx2D in eight of the nine clusters. The resulting regional frequency curves offer reliable estimates of extreme 2-day precipitation return values at any location within the study area. These findings are crucial for improving flood risk management, guiding infrastructure design, and supporting climate adaptation planning.