Comprehensive evaluation of trend analysis of extreme drought events in the Ceyhan River Basin, Turkey

The investigation of extreme meteorological drought events is crucial for disaster preparedness and regional water management. In this study, trends in extreme drought events, namely annual maximum drought severity (AMDS) and annual maximum drought duration (AMDD), were examined for the Ceyhan Basin. The analyses of extreme events were conducted using the standard precipitation index (SPI) index for multiple-time scales of 1, 3, 6, 9, and 12 months for 23 meteorological stations located in the Ceyhan Basin, Turkey. The Wallis-Moore and Wald-Wolfowitz methods were employed to determine the homogeneity of the data sets, whereas trend analyses were conducted using Mann-Kendall and Spearman Rho tests. The magnitude of trends was defined by Sen’s slope and linear regression, and change points were detected using the standard normal homogeneity test , Buishand’s range test, and Pettitt’s test. Although increasing trends were detected in most of the stations, only in nine of them , statistically significant results were noted at a significance level of 95%. The results of this paper provide valuable information to water resource management decision-makers in the Ceyhan River Basin for evaluating the effect of droughts and preparing for drought mitigation measures to avoid future drought risks. period in which a significant change occurs in a time series. In this study, the standard normal homogeneity test (SNHT), Buishand’s range test (BRT), and Pettitt’s test (PT) were employed to detect change points in the time series.