Majd et al. (2025) Stochastic evaluation of the effect of cross-correlation between precipitation and evapotranspiration on SPEI performance

Identification

• Journal: Journal of Hydrology
• Year: 2025
• Date: 2025-01-04
• Authors: Negar Rasouli Majd, Majid Montaseri, Babak Amirataee
• DOI: 10.1016/j.jhydrol.2024.132650

Research Groups

• Department of Water Engineering, Urmia University, Urmia, Iran

Short Summary

This study evaluates how the cross-correlation between precipitation and evapotranspiration influences the performance of the Standardized Precipitation Evapotranspiration Index (SPEI) across four different climatic zones compared to the Standardized Precipitation Index (SPI).

Objective

• To determine the effect of the cross-correlation coefficient between precipitation (P) and evapotranspiration (ET) on the ability of the SPEI to predict agricultural drought characteristics in arid, semi-arid, semi-humid, and humid climates.

Study Configuration

• Spatial Scale: Theoretical/Global (categorized by four climatic conditions: arid, semi-arid, semi-humid, and humid).
• Temporal Scale: Annual time series.

Methodology and Data

• Models used: Lag-one Multivariate Autoregressive Model [MAR(1)], Standardized Precipitation Evapotranspiration Index (SPEI), and Standardized Precipitation Index (SPI).
• Data sources: Stochastically generated data consisting of 10,000 pairs of long-term dependent annual precipitation (P) and evapotranspiration (ET) time series.

Main Results

• In arid, semi-arid, and semi-humid climates, the performance of SPEI in predicting drought characteristics is systematically dependent on the cross-correlation between precipitation and evapotranspiration.
• In humid climates, the performance of SPEI is independent of the cross-correlation between these two variables.
• For high cross-correlation values ($|R| \to 1$), the performance of SPEI converges and becomes nearly identical to that of the SPI.

Contributions

• The research clarifies existing inconsistencies in literature comparing SPEI and SPI.
• It provides a comprehensive guide for realistically inferring drought characteristics using SPEI, aiding in the more accurate interpretation of drought monitoring results.

Funding

• Not specified in the provided text.

Citation

@article{Majd2025Stochastic,
  author = {Majd, Negar Rasouli and Montaseri, Majid and Amirataee, Babak},
  title = {Stochastic evaluation of the effect of cross-correlation between precipitation and evapotranspiration on SPEI performance},
  journal = {Journal of Hydrology},
  year = {2025},
  doi = {10.1016/j.jhydrol.2024.132650},
  url = {https://doi.org/10.1016/j.jhydrol.2024.132650}
}