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 Institute Pirenaico de Ecologia in Zaragoza, Spain.^[1] 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.^[2]^[3]^[4]

The SPEI accounts not only for precipitation deficit but also for the role of the increased atmospheric evaporative demand on drought severity.^[5] 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.^[5]

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Datasets

Globally, the SPEIbase and Global Precipitation Climatology Centre (GPCC) drought index datasets are available at a relatively coarse spatial resolution. The SPEIbase is available at 0.5° resolution calculated from the Climatic Research Unit precipitation and potential evapotranspiration datasets. The GPCC drought index provides SPEI datasets at a 1.0° spatial resolution for limited timescales (1, 3, 6, 9, 12, 24, and 48 months).^[5]

Inputs to SPEI datasets can include high-resolution potential evapotranspiration (PET) from the Global Land Evaporation Amsterdam Model (GLEAM) and hourly Potential Evapotranspiration (hPET). GLEAM is a set of algorithms designed to calculate actual evaporation, PET, evaporative stress, and root-zone soil moisture.^[5]

Classification

SPEI Classification^[6]
Value	classification
2.0 or more	Extremely Wet
1.5 to 1.99	Very Wet
1.0 to 1.49	Moderate Wet
-0.99 to 0.99	Normal
-1.0 to -1.49	Moderate Dry
-1.5 to -1.99	Very Dry
-2.0 or less	Extremely Dry

References

^ Svoboda, Mark D.; Fuchs, Brian A. (2017-09-25), "Handbook of Drought Indicators and Indices*", Drought and Water Crises, Second edition. | Boca Raton : CRC Press, 2018. | 1st edition published in 2005.: CRC Press, pp. 155–208, doi:10.1201/b22009-11, ISBN 978-1-315-26555-1, retrieved 2023-05-18{{citation}}: CS1 maint: location (link)
^ Vicente-Serrano S.M.; Santiago Beguería; Juan I. López-Moreno (2010). "A Multiscalar Drought Index Sensitive to Global Warming: The Standardized Precipitation Evapotranspiration Index". Journal of Climate. 23 (7): 1696–1718. Bibcode:2010JCli...23.1696V. doi:10.1175/2009JCLI2909.1. S2CID 3826822.
^ Stagge, J. H.; Tallaksen, L. M.; Xu, C. Y.; Van Lanen, H. A. (2014). "Standardized precipitation-evapotranspiration index (SPEI): Sensitivity to potential evapotranspiration model and parameters". Hydrology in a changing world. IAHS-AISH Proceedings and Reports. Vol. 363. pp. 367–373. ISBN 9781907161414.
^ Tirivarombo, S.; Osupile, D.; Eliasson, P. (2018). "Drought monitoring and analysis: standardised precipitation evapotranspiration index (SPEI) and standardised precipitation index (SPI)". Physics and Chemistry of the Earth, Parts A/B/C. 106: 1–10. Bibcode:2018PCE...106....1T. doi:10.1016/j.pce.2018.07.001. S2CID 134507763.
^ ^a ^b ^c ^d Gebrechorkos, Solomon H.; Peng, Jian; Dyer, Ellen; Miralles, Diego G.; Vicente-Serrano, Sergio M.; Funk, Chris; Beck, Hylke E.; Asfaw, Dagmawi T.; Singer, Michael B.; Dadson, Simon J. (2023). "Global high-resolution drought indices for 1981–2022". Earth System Science Data. 15 (12): 5449–5466. Bibcode:2023ESSD...15.5449G. doi:10.5194/essd-15-5449-2023. hdl:10754/693396. ISSN 1866-3516.

Text was copied from this source, which is available under a Creative Commons Attribution 4.0 International License
^ Hayes, Michael J. (2006-10-13), "Drought Indices", Van Nostrand's Scientific Encyclopedia, Hoboken, NJ, USA: John Wiley & Sons, Inc., doi:10.1002/0471743984.vse8593, ISBN 0471743984, retrieved 2023-05-18