Investigation the Trend of Changes in Precipitation Extreme Indices in Khuzestan Province

In this study, in order to investigate the trend of precipitation changes in Khuzestan Province, the data used were daily, monthly and annual data of precipitation of selected synoptic stations for a statistical period of 30 years (1987-2016). To study the trend of precipitation changes, precipitation-related indices defined by the ETCCDMI expert group were estimated using RClimDex software. Then, the ascending and descending trend of changes in precipitation limit values ​​was investigated using Mann-Kendall non-parametric test method. The age slope estimator method was also used to determine the rate of precipitation change. The results showed that all precipitation-related indicators (except for the number of days with more than 25 mm and very wet days) had significant changes at the level of 5%. In terms of stations, Dezful station with 26.41% had the highest rainfall and Shushtar station with 3.64% had the lowest rainfall. Behbahan station also had a 14.87% increase in rainfall.