Standardised Precipitation Evapotranspiration Index

The Standardized Precipitation Evapotranspiration Index (SPEI) is a multiscalar drought index based on climatic data. It was developed by Vicente-Serrano et al. (2010) at the Pyrenean Institute of Ecology in Zaragoza, Spain.{{Citation |last1=Svoboda |first1=Mark D. |title=Handbook of Drought Indicators and Indices* |date=2017-09-25 |url=http://dx.doi.org/10.1201/b22009-11 |work=Drought and Water Crises |pages=155–208 |access-date=2023-05-18 |place=Second edition. {{!}} Boca Raton : CRC Press, 2018. {{!}} 1st edition published in 2005. |publisher=CRC Press |isbn=978-1-315-26555-1 |last2=Fuchs |first2=Brian A.|doi=10.1201/b22009-11 |url-access=subscription }} It can be used for determining the onset, duration and magnitude of drought conditions with respect to normal conditions in a variety of natural and managed systems such as crops, ecosystems, rivers, water resources, etc.{{cite journal |author1=Vicente-Serrano S.M. |author2=Santiago Beguería |author3=Juan I. López-Moreno |date=2010 |title=A Multiscalar Drought Index Sensitive to Global Warming: The Standardized Precipitation Evapotranspiration Index |journal=Journal of Climate|volume=23|issue=7|pages=1696–1718|doi=10.1175/2009JCLI2909.1|bibcode=2010JCli...23.1696V |s2cid=3826822 |doi-access=free |hdl=10261/202305 |hdl-access=free }}

The SPEI accounts not only for precipitation deficit but also for the role of the increased atmospheric evaporative demand on drought severity.{{Cite journal |last1=Gebrechorkos |first1=Solomon H. |last2=Peng |first2=Jian |last3=Dyer |first3=Ellen |last4=Miralles |first4=Diego G. |last5=Vicente-Serrano |first5=Sergio M. |last6=Funk |first6=Chris |last7=Beck |first7=Hylke E. |last8=Asfaw |first8=Dagmawi T. |last9=Singer |first9=Michael B. |last10=Dadson |first10=Simon J. |date=2023 |title=Global high-resolution drought indices for 1981–2022 |url=https://essd.copernicus.org/articles/15/5449/2023/ |journal=Earth System Science Data |language=en |volume=15 |issue=12 |pages=5449–5466 |doi=10.5194/essd-15-5449-2023 |issn=1866-3516 |doi-access=free|bibcode=2023ESSD...15.5449G |hdl=10754/693396 |hdl-access=free }} 50x50px Text was copied from this source, which is available under a Creative Commons Attribution 4.0 International License Evaporative demand is particularly dominant during periods of precipitation deficit. The SPEI calculation requires long-term and high-quality precipitation and atmospheric evaporative demand datasets. These can be obtained from ground stations or gridded data based on reanalysis as well as satellite and multi-source datasets.