Milan Stojković, Stevan Prohaska, Anđelija Koprivica Institute “Jaroslav Černi”, Belgrade , Serbia stevan.prohaska@jcerni.co.rs   Abstract Authors of this paper have managed to gather a significant number of hydro-meteorological time series from all over the globe. The longest series were selected in which linear trends were calculated and their internal structure analysed in order to determine frequency […]