Document Type : Original Article

Authors

• alireza parvishi ¹
• Behzad Saber ²
• Yusef Kheyruri ³

¹ Department of Civil Engineering, Ur.C., Islamic Azad University, Urmia, Iran

² Master's student Department of Civil Engineering, Ur.C., Islamic Azad University, Urmia, Iran

³ PhD student Departfment of Civil Engineering, S.R.C., Islamic Azad University, Tehran, Iran

Abstract

This study provides an integrated drought monitoring assessment for the Lake Urmia Basin using a combination of meteorological and satellite-based indicators over the period 2001–2024. Meteorological drought was analyzed using SPI and SPEI derived from precipitation and thermal stress conditions, while agricultural drought dynamics were evaluated using NDVI-based VCI, LST-based TCI, and the combined VHI index. The results indicate that 2008, 2017, 2023, and especially 2024 were the most critical drought years, where large parts of the basin recorded SPI and SPEI values below −1.5 and VCI and VHI values below 30%, indicating severe agricultural stress. In contrast, 2018 represented the peak recovery year, with over 70% of the basin showing NDVI values above 0.4 and TCI indicating minimal heat stress.

Quantitative analysis shows a strong negative thermal impact, where in 2024, more than 80% of the basin experienced LST above 315 K, coinciding with VHI values falling below 20%, marking the lowest vegetation resilience of the entire study period. Spatial-temporal comparison reveals that after 2021, climatic stress shifted from a rainfall-dominant drought pattern to a heat-driven drought regime, reducing the ecological recovery capacity of vegetation even in short wet spells. These findings highlight that future drought management in the Lake Urmia region must prioritize thermal stress mitigation alongside water resource planning.

Keywords

• Agricultural drought
• :Climatic drought
• :Urmia plain
• :Drought analysis

Main Subjects

• Water and hydraulic structures