A high-resolution view of the recent drought trends over the Iberian Peninsula

Droughts are a long-term weather-driven extreme event which occurs worldwide with great socio-economic impacts, namely in the Mediterranean and the Iberian regions. In a changing climate with rising temperatures, extreme events, such as droughts, are expected to increase in frequency and intensity, particularly in Mediterranean climates. In this context, the assessment of the evolution of drought in terms of its duration and intensity in the Iberian Peninsula (IP) is paramount, as it affects several socio-economic activities. The use of new high-resolution gridded datasets allows for the identification of patterns with finer temporal and spatial scales. In the current study, drought assessment in the IP was accomplished with both the Standardized Precipitation Evaporation Index (SPEI) and the Standardized Precipitation Index (SPI) for short-, medium- and long-timescales. A recently developed high-resolution dataset, Iberia01, was used, for the period 1971-2015, with 0.1 degrees horizontal resolution. The lower-resolution CRU dataset was also used. A clear drying trend in most of the IP is identified with both indices and both datasets. The trends of drought duration are also positive in most of the territory, whereas the mean drought intensity decreases slightly. The drivers of this drying trend are both the decreased precipitation and the increased reference evapotranspiration. The Iberia01 dataset allowed to identify more complex patterns of drought trends, mainly due to the improved representation of precipitation.

Automated summary

Droughts are a significant long-term weather phenomenon with great socio-economic impacts, particularly in regions like the Mediterranean and the Iberian Peninsula. With the changing climate and rising temperatures, extreme events, including droughts, are expected to increase in frequency and intensity. The use of high-resolution datasets is crucial in identifying complex patterns of drought trends in different regions.