Abstract
<jats:p>This paper examines drought detection in Italian catchments through a historical analysis of two meteorological indices: the Standardized Precipitation Index (SPI) and the Standardized Precipitation Evapotranspiration Index (SPEI) evaluated on the basis of the BigBang database (www.isprambiente.gov.it/pre_meteo/idro/BIGBANG_ISPRA.html) by the Italian Higher Institute for Environmental Protection and Research (ISPRA). The study focuses first on the characterization of drought indices into different scenarios and then a counting process based on statistical testing using a non-homogeneous Poisson process (NHPP) was applied to drought trends within each raster dataset. Finally, the proportion of drought trends within each catchment is determined based on the trends observed in individual raster grid cells. Hotspot analysis of drought indices is also conducted for each catchment, considering seasonal variations and geographic divisions across Italy. The results show that the Adige catchment, located in the Alpine region, exhibits the lowest drought index values during winter for both SPI and SPEI, which is consistent with the precipitation and evaporation patterns observed in Italian catchments.</jats:p>