نوع مقاله : مقاله پژوهشی
نویسنده
استادیار، گروه مهندسی آب، دانشگاه لرستان، خرم آباد، ایران
چکیده
کلیدواژهها
موضوعات
عنوان مقاله [English]
نویسنده [English]
This research investigates the variations in the distribution and quantity of winter precipitation at 18 stations located in the Dez River Basin, western Iran, during the period 1975-2024. The results from the modified Mann-Kendall test indicate that 50% of the stations (9 stations, including Takht Dareh, Keshvar, and Tang Pang Bakhtiari) have experienced a significant decreasing trend at the 5% level. According to the Sen's slope estimator, the most severe decreases (more than 3 mm per year) occurred at the Tang Pang Bakhtiari, Telezang, and Keshvar stations, which collectively led to a reduction of more than 150 mm over the study period. Temporal changes were primarily concentrated around two points: 1990 and 2006, indicating the influence of large-scale climatic factors. Furthermore, the analysis of the statistical distribution of data before and after the change points revealed a change in the distribution type (Changing from Weibull to Log-Normal based on Kolmogorov-Smirnov statistics) and significant changes in statistical indices such as variance and skewness at many stations. These findings are consistent with the predictions of IPCC reports and other regional studies and demonstrate that the decrease in winter precipitation is a large-scale challenge with serious implications for the region's water resources. The results also indicate changes in the form of the distribution function and severe changes in skewness in the sub-interval after the change point.
کلیدواژهها [English]
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