Internal stochastic structure of annual discharge time series of Serbia’s large rivers

Abstract

The internal structure of hydrologic processes is discussed in the paper. Time series of mean annual river discharges are assessed to determine their stationarity, trend and periodicity. The time series of annual discharges are determined to be non-stationary. The trend varies in different time segments, with changing trend intensity and direction. Hurst analysis shows that the time series of annual discharges have a long memory. Long-term periodicity of annual time series is considered, while macroperiods are determined and classified into four groups of mean values: 9.5, 13.5, 22.5 and 31.5 years. Secondary microperiodicity is found to exist in the interval from 3.6 to 4.9 years.