A Global Multiscale SPEI Dataset under an Ensemble Approach

A new multiscale Standardized Precipitation Evapotranspiration Index (SPEI) dataset is provided for a reference period (1960–1999) and two future time horizons (2040–2079) (2060–2099). The historical forcing based on combined climate observations reanalysis (WATer global CHange Forcing Dataset), the projections are fed by Fast Track experiment of Inter-Sectoral Impact Model Intercomparison Project under representative concentration pathways (RCPs) 4.5 8.5 an additional Earth system model (CMCC-CESM) forced RCP 8.5. To calculate potential evapotranspiration (PET) input to SPEI, Hargreaves–Samani Thornthwaite equations were adopted. This ensemble considers uncertainty due different models, development pathways, formulations. SPEI accumulation periods moisture deficit from 1 18 months starting in each month year, with focus within-period variability, excluding long-term warming effects PET. In addition supporting drought analyses, this also useful assessing wetter-than-normal conditions spanning one or more months. was calculated using SPEIbase package.