Investıgatıon of Drought Effect in Down Fırat Basın by Usıng Trend Analysıs Methods (Published)
In this study, trend analyses of annual mean temperature and annual total precipitation data were conducted at ten meteorological stations within the Lower Euphrates Basin for the period 1965–2025 years. The analyses employed the Mann-Kendall Test, Spearman’s Rho Correlation Test, Sen’s Slope Method, Innovative Trend Analysis (ITA), and Statistical Trend Analysis (IPTA). Temperature analyses revealed a statistically significant (p < 0.001) positive warming trend at all stations. The highest warming rate was observed at Gaziantep Merkez station (Sen’s slope: 0.0502 °C/year; Rho: 0.82), while the lowest was recorded at Şanlıurfa Birecik station (Sen’s slope: 0.0226 °C/year; Rho: 0.60). ITA/IPTA graphs confirmed that warming occurred homogeneously and systematically across low, medium, and high temperature quantiles at all stations.Precipitation data exhibited notable differences among stations. The highest negative trend value was observed at Malatya Doğanşehir station (Sen’s slope: -0.1762 mm/year; p = 0.017), representing the strongest aridification signal in the study. This was followed by Şanlıurfa Birecik (Sen’s slope: -0.1625 mm/year; p = 0.012), Şanlıurfa Haliliye (Sen’s slope: -0.1572 mm/year; p = 0.089), Elazığ Palu (Sen’s slope: -0.1424 mm/year; p = 0.080), and Elazığ Keban (Sen’s slope: -0.1082 mm/year; p = 0.104). Malatya Yeşilyurt station also exhibited a statistically significant decreasing trend (Sen’s slope: -0.0955 mm/year; p = 0.047). In contrast, Elazığ Merkez showed near-stationary conditions (Sen’s slope: 0.03 mm/year; p = 0.686), while Şanlıurfa Siverek displayed a slight decline (Sen’s slope: -0.0634 mm/year; p = 0.677). Adıyaman Merkez (Sen’s slope: -0.0824 mm/year; p = 0.502) and Gaziantep Merkez (Sen’s slope: -0.0732 mm/year; p = 0.448) also showed decreasing tendencies, though these trends were not statistically significant.The most critical finding of the study is that stations where temperature increases coincide with precipitation decreases in Malatya Doğanşehir, Şanlıurfa Birecik, Şanlıurfa Haliliye, Elazığ Palu, and Elazığ Keban, face an increasing thermal stress on the hydrological water budget and a heightened risk of aridification. In particular, the precipitation decline of -0.1762 mm/year at Malatya Doğanşehir and the Spearman’s Rho coefficient of -0.32 at Şanlıurfa Birecik indicate that the aridification trend at these stations has gained a systematic character. In conclusion, a pronounced warming trend is occurring in the Lower Euphrates Basin due to climate change, with statistically significant decreases in precipitation regimes, particularly in the southern and eastern parts of the basin. This situation underscores the urgent need for strategic measures in water resources management and agricultural sustainability in the region.
Keywords: Climate Change, ITA/IPTA, Mann-Kendall, drought, lower euphrates basin, trend analysis