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High spatial resolution climatology of drought events for Spain: 1961–2014

Abstract:

This study characterizes the climatology of drought events over the mainland Spain and the Balearic Islands using high-resolution (1.21 km2) meteorological data from 1961 to 2014. The climatology of drought was assessed based on two widely-recognized drought indices: the Standardized Precipitation Index (SPI) and the Standardized Precipitation-Evapotranspiration Index (SPEI), considering four different timescales (1-, 3-, 6- and 12-months). Drought events were simply defined as sequences of months with negative values of the indices. We analysed the spatial and temporal variability of the frequency, duration and magnitude of the drought events. In general, the frequency of drought events is higher in the northern than in the southern regions. Conversely, the average duration and magnitude of the drought events in central and southwestern regions duplicate those recorded in northern areas. Although drought characteristics exhibit a general north–south gradient irrespective of the drought timescale and the drought index analysed, we found important spatial differences in terms of both drought duration and severity. As opposed to the SPI, the SPEI shows, on average, higher drought durations and magnitudes at 1-, 3- and 6-months timescales. Albeit of the absence of significant temporal changes in drought duration or magnitude at the regional scale, a nonsignificant tendency toward higher drought duration and magnitude is observed over the majority of Spain. Our result provide valuable guidance to stakeholders and decision-makers on detecting, monitoring and adapting to drought impacts at local, regional and national scale in Spain.