Blain et al. (2026) SPEIChanges: A framework for assessing climate-change-driven shifts in drought frequency using the standardized precipitation evapotranspiration index

Identification

• Journal: Environmental Modelling & Software
• Year: 2026
• Date: 2026-09-02
• Authors: Gabriel Constantino Blain, Graciela da Rocha Sobierajski, Letícia Lopes Martins
• DOI: 10.1016/j.envsoft.2026.107158

Research Groups

• Agronomic Institute - Agricultural Biosystems and Post-Harvest Center
• Embrapa Digital Agriculture, Brazilian Agricultural Research Corporation
• Agronomic Institute – Fruits Center
• Agronomic Institute – Soil Center

Short Summary

This study presents SPEIChanges, a framework for assessing climate-change-driven shifts in drought frequency using the Standardized Precipitation Evapotranspiration Index. The method quantifies how changes in precipitation patterns affect drought occurrence and can detect and quantify changes in drought frequency even when traditional methods fail.

Objective

• To develop an extension of SPIChanges to SPEI, allowing for the assessment of climate-change-driven shifts in drought frequency using the Standardized Precipitation Evapotranspiration Index.
• To evaluate the performance of SPEIChanges under contrasting global historic and future climatic conditions.

Study Configuration

• Spatial Scale: Global, with a focus on Brazil and Oxford, UK.
• Temporal Scale: Historical (1827-2020) and future (2030-2100) climate projections.

Methodology and Data

• Models used: Generalized Extreme Value (GEV) distribution for nonstationary modeling of P-AED series.
• Data sources: Climate Research Unit Time Series version 4.09 (CRU TS v4.09), Physical Sciences Laboratory, part of National Oceanic and Atmospheric Administration (NOAA-PSL).

Main Results

• SPEIChanges is capable of quantifying changes in drought frequency under climate change conditions.
• The method can detect and quantify changes in drought frequency even when traditional methods fail.
• SPEIChanges adjusts the expected frequency of drought events to current climate conditions.

Contributions

• Original value of the article with respect to existing literature: SPEIChanges provides a new framework for assessing climate-change-driven shifts in drought frequency using the Standardized Precipitation Evapotranspiration Index.
• The method can detect and quantify changes in drought frequency under climate change conditions, providing valuable insights for water resource management.

Funding

• This research was funded by the Agronomic Institute - Agricultural Biosystems and Post-Harvest Center.

Citation

@article{Blain2026SPEIChanges,
  author = {Blain, Gabriel Constantino and Sobierajski, Graciela da Rocha and Martins, Letícia Lopes},
  title = {SPEIChanges: A framework for assessing climate-change-driven shifts in drought frequency using the standardized precipitation evapotranspiration index},
  journal = {Environmental Modelling & Software},
  year = {2026},
  doi = {10.1016/j.envsoft.2026.107158},
  url = {https://doi.org/10.1016/j.envsoft.2026.107158}
}