Characterization of meteorological drought variability over the Tigris-Euphrates Basin, Türkiye, using SPI and SPEI
ACTA GEOPHYSICA, cilt.74, sa.5, 2026 (SCI-Expanded, Scopus)
- Yayın Türü: Makale / Tam Makale
- Cilt numarası: 74 Sayı: 5
- Basım Tarihi: 2026
- Doi Numarası: 10.1007/s11600-026-01997-z
- Dergi Adı: ACTA GEOPHYSICA
- Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Aerospace Database, Compendex, Geobase, INSPEC, Academic Search Ultimate (EBSCO), Natural Science Collection (ProQuest), Earth, Atmospheric, & Aquatic Science Collection (ProQuest), Materials Science & Engineering Collection (ProQuest), Technology Collection (ProQuest)
- Karadeniz Teknik Üniversitesi Adresli: Evet
Özet
Meteorological drought is a complex hydroclimatic hazard that develops gradually through persistent precipitation deficits and can propagate to water resources, ecosystems, agriculture, and socioeconomic systems. However, when climatic water balance conditions influence drought development, precipitation-based indices alone may not be fully suitable for characterizing meteorological drought variability. This study has investigated the meteorological drought characteristics over the Tigris-Euphrates Basin, T & uuml;rkiye. The long-term monthly precipitation and temperature data were collected from 16 meteorological stations for the periods of 1965-2025. The Standardized Precipitation Index (SPI) and Standardized Precipitation Evapotranspiration Index (SPEI) were calculated at 3-, 6-, and 12-month accumulation scales to compare precipitation-based and climatic water balance-based drought signals. Drought conditions were assessed using drought frequency, severity class distribution, monthly SPI-SPEI differences, spatial patterns of severe-to-extreme drought frequency, and event-scale metrics including duration, cumulative severity, and peak intensity. The results show that SPI and SPEI produced broadly similar drought signals at the 3-month scale, whereas differences became more evident at seasonal and annual scales. SPEI-12 generally identified higher drought frequencies and longer drought durations at several stations, indicating the importance of climatic water balance conditions in characterizing drought persistence. However, SPI-12 produced higher extreme drought frequencies and greater cumulative event severity at selected stations, showing that SPI and SPEI are not interchangeable drought indicators. Major drought episodes clustered around 1970-1971, 1999-2002, 2012-2015, and 2019-2023, with the recent 2019-2023 period appearing prominently across multiple stations. Overall, the findings demonstrate that station-based SPEI provides complementary information to SPI and improves the characterization of drought frequency, persistence, and spatial variability in the Tigris-Euphrates Basin. The dual-index framework supports more robust meteorological drought monitoring in basins where both precipitation variability and climatic water balance processes influence drought development.