Monthly Standardized Precipitation-Evapotranspiration Index (SPEI) 1990 - 2024 for Ebro basin, Spain at 1km

Gridded monthly precipitation and air temperature datasets were used to compute the Standardized Precipitation Evapotranspiration Index (SPEI) at a 3-month accumulation timescale for Ebro basin in Spain at 1km scale. SPEI integrates precipitation and temperature information through the estimation of potential evapotranspiration (PET), which was calculated using the Thornthwaite method (Thornthwaite, 1948) with the outcomes being modelled using a logarithmic distribution. SPEI calculations were performed using a continuous approach implemented in the MiraMon GIS&RS software (Pons, 2000)(https://www.miramon.cat/Index_eng.htm). The calculation was performed over the period 1990–2024 to ensure a sufficient long period for robust anomaly estimation. Monthly mean air Temperature (Tmean, °C) and monthly aggregated precipitation (P, mm) were compiled from in situ meteorological observations. Greatest accuracy and station coverage was ensured by combining meteorological networks sources from Spain (AEMET (Agencia Estatal de Meteorología), XEMA - Meteocat (Servei Meteorològic de Catalunya), SAIH (Sistema Automático de Información Hidrológica), SIAR (Sistema de Información Agroclimática para el Regadío), Tragsatec (Tecnologías y Servicios Agrarios, S.A.) and France (Météo France). The resulting dataset spanned from 1990 to 2024 and included data from 2535 meteorological stations distributed across the entire basin. Each zip file corresponds to one year and includes 12 monthly SPEI3 files. *Date format : SPEI3_MM_YYYY.tiff