 Standardised Precipitation Evapotranspiration Index

The Standardized Precipitation Evapotranspiration Index (SPEI) is a drought index that aims to quantify the intensity and duration of drought conditions by taking into account both precipitation and potential evapotranspiration (PET). Developed in the context of climate studies, SPEI offers a more comprehensive assessment of drought by incorporating the balance between water supply (precipitation) and water demand (evapotranspiration).