Susceptibility of the Iberian Peninsula to extreme precipitation and aridity: a high-resolution analysis for 1950–2022

This study consisted of the assessment of the Iberian Peninsula’s (IP) susceptibility to precipitation extreme events (PEE) and aridity across a long historical period of 1950–2022 and a shorter period of 1981–2022, based on the calculation of eight extreme precipitation and two aridity indices. Furthermore, two recently developed extreme precipitation susceptibility indices were also applied, namely a composite index and a principal component analysis-based index. ERA5-Land reanalysis data were used for those calculations, previously bias-corrected with the Iberia01 observational dataset as a baseline in their overlapping period of 1971–2015, following a quantile-mapping approach. A trend analysis performed for the two periods reveals an annual and seasonal drying trend over southwestern, central, and northeastern regions, as well as a wetting trend over the southeast annually. Regarding the PEE contribution to total precipitation (which is higher over eastern IP, and around 24% to 28%), it is increasing in several coastal regions during winter, and in north-central regions during summer and annually. High to very high susceptibility areas, which correspond to approximately 50% of the IP, are located on the mountains’ Atlantic-facing (western IP mountains) or Mediterranean-facing (eastern IP mountains) side, while the inner IP plateaus reveal low to moderate susceptibility. Our results agree with previous studies and show with high detail the susceptibility to PEEs and the recent past trends of all IP regions, which is a novelty comparatively to those studies. This highly detailed information can be used, e.g., to improve the assessment and mitigation of urban flood risks, mitigate water scarcity in the agro-food industry, or prevent crop destruction during extreme precipitation events.