Assessment of droughts in the Iberian Peninsula using the WASP ‐Index

This paper analyses the temporal and spatial variability of droughts in Iberia (IP) and in five IP regions (1951−2007) using four observational precipitation‐gridded data sets. Droughts were analysed by means of the Weighted Anomaly of Standardized Precipitation (WASP) for 3‐, 6‐ and 12‐month time scales. WASP‐Index and the Standardized Precipitation Index are highly correlated. The major drought spells at Iberian scale are identified by the four data sets. Moreover, the droughts frequency and severity increased from the late 1980s. Finally, in western Iberia, statistically significant drying trends are detected. In eastern Iberia, larger uncertainties are found on the trends signal.