Gül et al. (2026) A Skewness–Kurtosis Adjusted Expansion of the Standardised Precipitation Index for Drought Analysis

⚠️ Warning: This summary was generated from the abstract only, as the full text was not available.

Identification

• Journal: International Journal of Climatology
• Year: 2026
• Date: 2026-07-30
• Authors: Murat Gül, Yavuz Selim Güçlü
• DOI: 10.1002/joc.70531

Research Groups

Not specified in the provided text.

Short Summary

The study proposes the eXpanded SPI (X-SPI), a drought index that adjusts the classical Standardized Precipitation Index (SPI) by incorporating skewness and kurtosis to better account for local precipitation variability.

Objective

• To develop a probabilistic standardization framework (X-SPI) that integrates skewness (via a median-based shift) and kurtosis (via a variability-driven re-scaling term) to improve the characterization of drought as a natural hazard.

Study Configuration

• Spatial Scale: 148 meteorological stations across Türkiye.
• Temporal Scale: 1966–2020.

Methodology and Data

• Models used: eXpanded SPI (X-SPI), classical SPI, and median-adjusted SPI (M-SPI).
• Data sources: Precipitation records from meteorological stations (annual and multi-scale accumulated totals).

Main Results

• The re-scaling component, derived from the coefficient of variation ($C_v$), successfully adjusts the position of standardized values relative to conventional classification thresholds based on station-specific variability.
• The re-scaling term modulates the net magnitude of the skewness-related shift component.
• Drought and wetness class assignments vary depending on the local variability regime, indicating that X-SPI is more sensitive to the underlying distribution of the data than classical SPI.

Contributions

• Provides a more distribution-sensitive monitoring framework for drought by accounting for higher-order moments (skewness and kurtosis) while maintaining the operational structure of probabilistic standardization.

Funding

Not specified in the provided text.

Citation

@article{Gül2026SkewnessKurtosis,
  author = {Gül, Murat and Güçlü, Yavuz Selim},
  title = {A Skewness–Kurtosis Adjusted Expansion of the Standardised Precipitation Index for Drought Analysis},
  journal = {International Journal of Climatology},
  year = {2026},
  doi = {10.1002/joc.70531},
  url = {https://doi.org/10.1002/joc.70531}
}