The Features of the Cyclical Fluctuations, Homogeneity and Stationarity of the Average Annual Flow of the Southern Buh River Basin

Abstract In the last decades, according to researches of scientists of the world becomes more evident that the global and regional climate changes impact on the water regime of rivers and leads to break of the stationarity of observations series. In this study we analysed the long-term (since the beginning of the observations to 2012) average annual flow of the Southern Buh River Basin (37 gauging stations) and its cyclical fluctuations during a long period of time. The methodological approaches based on the using of hydro-genetic methods for estimation the homogeneity and stationarity of hydrological series were used. We researched that series of observations are homogeneous and stationary. However, not all series of observations were representative for determination of the stable average value. The presented results illustrate that the long-term fluctuations of the average annual flow at all gauging stations is synchronous. Therefore, the climatic conditions of the flow formation are homogeneous. However, these fluctuations are not always synchronous phase. We found out that the average annual flow in this basin fluctuates and has decreasing trend in the last decade. It is due to cyclical fluctuations of the river flow. We calculated the statistical parameters for all gauging stations.