Identification of temporal fluctuations in the annual flood series of Karoun and Dez rivers in Iran

摘要

Annual flood series in seven main stations in the Large Karoun river (consist of Karoun and Dez rivers) in Iran, measured during 1958 - 2009, were examined to identify the temporal character of changes in flood series . Two approaches were used to evaluate temporal changes in flood series during the period 1958 -2009. The first approach is based on an analysis of standardized departures, and the second approach based on a Multiple trend tests were computed by varying the beginning and ending date ofthe time series.These method are used for identification of an abrupt change in flood series rather than a gradual trend. Results indicate a noticeable step increase in flood series around 1983 rather than as a gradual trend. This step change is that theclimate system has shifted to a new regime that will likely remain relatively constant until a new shift or step change occurs.