Scaling properties of the runoff variations in the arid and semi-arid regions of China: a case study of the Yellow River basin

We analyzed long daily runoff series at six hydrological stations located along the mainstem Yellow River basin by using power spectra analysis and multifractal detrended fluctuation analysis (MF-DFA) technique with aim to deeply understand the scaling properties of the hydrological series in the Yellow River basin. Research results indicate that: (1) the runoff fluctuations of the Yellow River basin exhibit self-affine fractal behavior and different memory properties at different time scales. Different crossover frequency (1/f) indicates that lower crossover frequency usually corresponds to larger basin area, and vice versa, showing the influences of river size on higher frequency of runoff variations. This may be due to considerable regulations of river channel on the runoff variations in river basin of larger basin size; (2) the runoff fluctuations in the Yellow River basin exhibit short-term memory properties at smaller time scales. Crossover analysis by MF-DFA indicates unchanged annual cycle within the runoff variations, implying dominant influences of climatic changes on changes of runoff amount at longer time scales, e.g. 1 year. Human activities, such as human withdrawal of freshwater and construction of water reservoirs, in different reaches of the Yellow River basin may be responsible for different scaling properties of runoff variations in the Yellow River basin. The results of this study will be helpful for hydrological modeling in different time scales and also for water resource management in the arid and semi-arid regions of China.