Author(s): Guifang Yang
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Keywords: R/S analysis; Spatial and temporal characteristics; Discharge and SSC; Middle reaches of Yangtze River
Abstract: Based largely on the daily database of discharge and suspended sediment concentration (SSC) from 1950s to 1980s, the spatial and temporal fractal characteristics are discussed using rescaled range (R/S) analysis for the river sections where Yichang, Jianli, Luoshan and Hankou hydrological gauging stations in the middle reache of Yangtze River are located. The results obtained by the R/S method reveal that all of Hurst exponents are larger than 0.5 with a range from 0.58 to 0.85, indicating that discharge and SSC fluctuations in the middle reache of Yangtze River are persistent in the past several decades. Of note, different results occur among the stations due to multiple influence factors. In Yichang, the Hurst exponents are from 0.64 to 0.72 revealing the relatively steady sources of discharge and SSC. In Jianli, Luoshan and Hankou, a series of oscillations documented by Hurst exponents are detected from high discharge and low SSC to low discharge and high SSC, which can be interpreted as the result of coupling function between the Yangtze River and the Dongting Lake together with the self adjustment of river to the cutting engineering. In addition, the temporal features of Hurst exponents are clear, largely characterized by decreased persistence of discharge and alternating high and low SSC. Furthermore, similar hydraulic factors and boundary conditions at Luoshan and Hankou result in almost the same changes of Hurst exponents.
Year: 2004