Characteristics and Multifractal Properties of Daily Streamflow in a Semiarid Environment: Fid-Bau Portal

Characteristics and Multifractal Properties of Daily Streamflow in a Semiarid Environment

Emadi, S. / Khalili, D. / Movahed, S. M. Sadegh

Abstract Multifractality of daily streamflow time series data was investigated for ten hydrometric stations of the semiarid Karkheh watershed (western Iran). Mann–Kendall test results indicated nonsignificant trend (at 95 % confidence level) in the annual streamflow time series data of all stations. We applied multifractal detrended fluctuation analysis technique to detect characteristics and multifractal properties of daily streamflow time series data. The Hurst exponent (H) values in all of the stations varied between 0.5 and 1, showing long memory (persistence), except Aran Gharb station, which indicated short memory (anti-persistence). Fluctuation function, F q (s), versus s detected crossovers representing streamflow temporal scaling of 310–400 days at the studied stations, which corresponds to 1 year. Results confirmed multifractality of daily streamflow time series data in all stations, as evidenced by the q relationships with h(q), τ(q) and D(q) and also the singularity spectrum f(α) versus α relationships. Analyses of shuffled and surrogated streamflow series demonstrated that multifractality is due to both PDF and long-range correlation properties. According to the results, similar patterns of hydrological characteristics and streamflow generation mechanisms exist across the study area.