Document Type : Research Paper
Authors
1 Assistant Prof., Watershed Management Department, Soil Conservation & Watershed Management Research Institute (SCWMRI), AREEO, Tehran, Iran
2 Associate Professor, Department of drought and climate change, Soil conservation & watershed Management Research Institute (SCWMRI), AREEO, Tehran, Iran
Abstract
Introduction
Drought is one of the most destructive natural hazards, causing severe impacts on water resources, agriculture, and ecosystems. Because of the climatic heterogeneity of Kermanshah Province, western Iran, a single drought index cannot accurately represent drought conditions across different climatic zones. This study evaluated the Standardized Precipitation Index (SPI), Rainfall Anomaly Index (RAI), Standardized Index of Annual Precipitation (SIAP), and Reconnaissance Drought Index (RDI) to identify the most suitable index for each climatic region.
Materials and Methods
Meteorological drought was analyzed in the cold, warm, and temperate climatic zones of Kermanshah Province during 2001–2024. SPI was selected as the reference index because of its widespread use and statistical reliability. The performance of RAI, SIAP, and RDI was evaluated by comparing their correlations with SPI to identify the most appropriate index for each climatic zone.
Results and Discussion
All drought indices showed similar temporal patterns and identified 2008 as the most severe drought year. However, their performance varied among climatic regions. In the warm regions of Sarpol-e Zahab and Gilan-e Gharb, RDI showed the strongest agreement with SPI, with correlation coefficients of 0.78 and 0.76, respectively (p < 0.01). In the cold regions of Kangavar and Sonqor, SIAP showed the highest correlations with SPI (0.77 and 0.75, respectively; p < 0.01). In the temperate climatic zone, all evaluated indices showed comparable performance.
Conclusion
The results demonstrate that the performance of meteorological drought indices depends on regional climatic conditions. Although all indices showed similar drought patterns, their accuracy differed among climatic zones. RDI was more suitable for warm climates, whereas SIAP performed better in cold climates. Selecting climate-specific drought indices can improve drought monitoring, reduce assessment uncertainty, and support watershed management, water resources planning, agricultural management, and drought adaptation strategies.
Keywords
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