Indicator Explorer

Search indicator
High income
Upper middle income
Lower middle income
Low income

Income groups

Geographic regions

Climate classification


Highest and lowest scoring countries

XX. Highest Value
XX. Lowest Value

Indicator details

License Type
Open Data Commons Open Database License (ODbL) v1.0
Indicator Name
Standardised Precipitation-Evapotranspiration Index
Long definition
The SPEI fulfils the requirements of a drought index since its multi-scalar character enables it to be used by different scientific disciplines to detect, monitor and analyze droughts. Like the sc-PDSI and the SPI, the SPEI can measure drought severity according to its intensity and duration, and can identify the onset and end of drought episodes. The SPEI allows comparison of drought severity through time and space, since it can be calculated over a wide range of climates, as can the SPI.
Global SPEI database (SPEIbase).
Environment: Climate risk & resilience
Aggregation method
Standardized values over the emerged land pixels.
Statistical concept and methodology
The Global SPEI database, SPEIbase, offers long-time, robust information about drought conditions at the global scale, with a 0.5 degrees spatial resolution and a monthly time resolution. It has a multi-scale character, providing SPEI time-scales between 1 and 48 months.
Development relevance
Drought is a major cause of agricultural, economic and environmental damage. Drought effects are apparent after a long period with a shortage of precipitation, making it very difficult to determine their onset, extent and end. Thus, it is hard to objectively quantify the characteristics of drought episodes in terms of their intensity, magnitude, duration and spatial extent. Much effort has been devoted to developing techniques for drought analysis and monitoring. Among these, the definition of quantitative indices is the most widespread approach, but subjectivity in the definition of drought has made it very difficult to establish a unique and universal drought index. Most studies related to drought analysis and monitoring systems have been conducted using either i) the Palmer Drought Severity Index (PDSI) (Palmer, 1965), based on a soil water balance equation, or ii) the Standardised Precipitation Index (SPI; McKee et al., 1993), based on a precipitation probabilistic approach.
Other notes
The data presented in the Sovereign ESG Data Portal is the 12-month time-scale.
Related source links
License URL