Optimal distribution functions for drought characterization across Europe’s climatic gradient

Résumé fourni par la source

Study region This study focuses on pan-European climatic regimes, evaluating drought characterization at the Nomenclature of Territorial Units for Statistics level (NUTS-3). Study focus Accurate statistical characterization of drought events is essential for effective water resources management and disaster risk reduction, yet the selection of appropriate probability distributions remains uncertain under regional climatic diversity. This study develops a rigorous methodological framework for optimizing drought characterization through systematic probability distribution function (PDF) selection. Eight candidate PDFs were evaluated for characterizing meteorological and hydrological drought. We calculated the standardized precipitation index (SPI-3), standardized precipitation evapotranspiration index (SPEI-3), and standardized streamflow index (SSI-3) at 3-month timescale using L -moments for parameter estimation. A two-stage selection process was then applied, using the Anderson-Darling test and corrected Akaike Information Criterion. New hydrological insights for the region Results show optimal PDF selection is climate-dependent, indicator-specific, and seasonally variable. For SPI-3, the Gamma (GAM) distribution dominates across most European climate zones, validating conventional approaches for precipitation-based indices. SPEI-3 exhibits spatial heterogeneity, with the Pearson Type III being recommended for central and western European climates, and the Normal distribution for Scandinavia and Mediterranean regions. SSI-3 is the most spatially variable, with LN3 recommended across central and western Europe, GAM for northern Scandinavia and parts of the Mediterranean, and GEV in the Baltic region and scattered coastal and southern regions.

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