CHARACTERIZING EXTREME DROUGHT EVENTS IN PORTUGAL ON DIFFERENT TIME SCALES - CONTRIBUTION FOR AN OPTIMUM ENERGY MANAGEMENT

Drought is a major natural hazard having widespread environmental and related socioeconomic negative impacts all over the world. In Portugal it is one of the most frequent climatic extreme events. In this study the multiscalar Standardized Precipitation Evapotranspiration Index (SPEI) gridded dataset, with a regular resolution of 0.5 degrees and covering the period between January 1901 and December 2012, is used to characterize the spatio-temporal variability of extreme drought events occurring over mainland Portugal. The analysis is performed for extreme drought events, here defined by SPEI values under a certain threshold (SPEI < -1.28), for the time scales of 6, 12, 18 and 24 months. Results show that there is a noticeable distinction between drought characteristics on the northern and southern regions of Portugal, on the shorter timescale (6 months). Additionally the high correlations (ranging from 85% to 74%) between SPEI values on the north of Portugal and hydroelectric (>10 MW) production suggest that detailed information on future projections on extreme drought events may be an essential contribution for optimum management, adaptation and mitigation strategies and decision on the use of surface water resources and thus on related energy generation.