Linear and non-linear scaling of the Yangtze River flow

Abstract

Power law correlation properties of sign and magnitude series have been studied based on the series of observation records of flow of the River Yangtze. The results obtained give improved insight into and understanding of the linear and non-linear processes of the water cycle. With the newly developed Delayed Vector Variance method and the surrogate test, the documented linkage between the sign series and the linear process, and that between the magnitude series and non-linear process can be verified. The spectra estimated by detrended fluctuation analysis method show different properties of intra-annual and inter-annual correlations in both sign and magnitude series. The linear process behaves as an 1/f noise at a time scale less than about 60 days, but shows features of anti-persistence in terms of long-term fluctuation. The magnitudes are clustered in three ways mainly caused by non-linear processes, i.e. periodic clustering, strong short-term clustering of 1/f noise at time scales less than 20 days, and long-term clustering with weak persistence. Copyright © 2007 John Wiley & Sons, Ltd.