Gridded monthly 3-month Standardized Precipitation-Evapotranspiration Index (SPEI) at uniform grid resolution of 0.05° by 0.05° used in Gascoigne et al. (2024).
The SPEI is a multi-scalar drought index based on climatic data. It is a ratio of actual to potential evapotranspiration. The values are Z-values based on 3 the prior months..
The underlying data are at a resolution of 0.5° (~5.5 km).
Source of underlying data: Sergio M. Vicente-Serrano, Instituto Pirenaico de Ecología, Zaragoza, Spain. Santiago Beguería, Estación Experimental de Aula Dei, Zaragoza, Spain. (https://spei.csic.es/)