<p>Drought represents a major environmental and socio-economic hazard in semi-arid regions, where flash droughts—characterized by rapid onset—pose acute threats to agriculture, food security, and water resources. Despite their growing prominence and severe impacts, accurate detection and monitoring of these abrupt events remain challenging, particularly in data-scarce semi-arid areas. This study introduces a multi-index framework to assess drought dynamics in North Khorasan province, Iran, combining the Standardized Precipitation Evapotranspiration Index (SPEI), Evaporative Stress Index (ESI), and a modified Flash Drought Intensity Index (FDII). Monthly data from 2001 to 2022 were analyzed across six cities using Mann–Kendall and Sen’s slope trend tests, ARIMA-based simulations, Generalized Extreme Value (GEV) modeling, and wavelet spectral analysis. The results reveal recurrent severe drought episodes during the 2010s—particularly in 2008, 2010, and 2021—accompanied by increasing frequency and severity of flash droughts, most notably in Maneh and Samalqan and Shirvan. Analyses were conducted using monthly ESI data (5-km resolution) and SPEI-1 from 2001 to 2022. Wavelet coherence and power spectrum analyses identify dominant 2–4-year climatic oscillations and strong multi-scale synchronization between meteorological and vegetation-based indices. Rolling correlation analysis reveals localized variability and temporal decoupling, especially during anomalous years such as 2013. ARIMA–GEV modeling highlights spatial heterogeneity in drought extremes, with Esfarayen and Faruj showing higher tail risks and greater variability. FDII-based assessments confirm the rising frequency and severity of flash droughts—again most pronounced in Maneh and Samalqan and Shirvan—underscoring the region’s increasing vulnerability to rapid hydrometeorological shifts. These findings demonstrate the value of integrating satellite-derived indices with advanced analytical tools to enhance drought hazard monitoring and early warning in semi-arid environments. The proposed framework offers practical insights for climate-resilient agricultural planning, adaptive water resource management, and long-term disaster preparedness. Future research should prioritize incorporating soil moisture observations, higher-resolution remote sensing data, and region-specific threshold calibration to improve flash drought detection, reduce vulnerability, and support risk-informed adaptation strategies.</p>

Multi-index assessment of flash drought hazards in North Khorasan province, northeastern Iran

期刊论文
发表日期：

2026年4月16日

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Mehdi Teimouri

摘要

Drought represents a major environmental and socio-economic hazard in semi-arid regions, where flash droughts—characterized by rapid onset—pose acute threats to agriculture, food security, and water resources. Despite their growing prominence and severe impacts, accurate detection and monitoring of these abrupt events remain challenging, particularly in data-scarce semi-arid areas. This study introduces a multi-index framework to assess drought dynamics in North Khorasan province, Iran, combining the Standardized Precipitation Evapotranspiration Index (SPEI), Evaporative Stress Index (ESI), and a modified Flash Drought Intensity Index (FDII). Monthly data from 2001 to 2022 were analyzed across six cities using Mann–Kendall and Sen’s slope trend tests, ARIMA-based simulations, Generalized Extreme Value (GEV) modeling, and wavelet spectral analysis. The results reveal recurrent severe drought episodes during the 2010s—particularly in 2008, 2010, and 2021—accompanied by increasing frequency and severity of flash droughts, most notably in Maneh and Samalqan and Shirvan. Analyses were conducted using monthly ESI data (5-km resolution) and SPEI-1 from 2001 to 2022. Wavelet coherence and power spectrum analyses identify dominant 2–4-year climatic oscillations and strong multi-scale synchronization between meteorological and vegetation-based indices. Rolling correlation analysis reveals localized variability and temporal decoupling, especially during anomalous years such as 2013. ARIMA–GEV modeling highlights spatial heterogeneity in drought extremes, with Esfarayen and Faruj showing higher tail risks and greater variability. FDII-based assessments confirm the rising frequency and severity of flash droughts—again most pronounced in Maneh and Samalqan and Shirvan—underscoring the region’s increasing vulnerability to rapid hydrometeorological shifts. These findings demonstrate the value of integrating satellite-derived indices with advanced analytical tools to enhance drought hazard monitoring and early warning in semi-arid environments. The proposed framework offers practical insights for climate-resilient agricultural planning, adaptive water resource management, and long-term disaster preparedness. Future research should prioritize incorporating soil moisture observations, higher-resolution remote sensing data, and region-specific threshold calibration to improve flash drought detection, reduce vulnerability, and support risk-informed adaptation strategies.