摘要：Assessing the probability of occurrence of drought is important for improvingcurrent drought assessment, management and mitigation measures, and strategiesacross Spain. This study employed two well-established drought indices, theStandardized Precipitation Index (SPI) and the Standardized PrecipitationEvapotranspiration Index (SPEI), to characterize drought duration andmagnitude at different timescales over Spain. In order to map the droughthazard probability, we applied the extreme value theory and tested differentthresholds to generate peak-over-threshold (POT) drought duration andmagnitude series. Our results demonstrate that the generalized Pareto (GP)distribution performs well in estimating the frequencies of drought magnitudeand duration. Specifically, we found a good agreement between the observed andmodelled data when using upper percentiles to generate the POT series.Spatially, our estimations suggest a higher probability of extreme droughtevents in southern and central Spain compared to the northern and easternregions. Also, our study found spatial differences in drought probabilityestimations as a function of the selected drought index (i.e. SPI vs. SPEI)and timescale (i.e. 1, 3, 6, and 12 months). Drought hazard probability mapscan contribute to the better management of different sectors (e.g. agriculture,water resources management, urban water supply, and tourism) at national,regional, and even local scale in Spain.
