Detecting Annual and Seasonal Hydrological Change Using Marginal Distributions of Daily Flows

Changes in the hydrological regime are widely investigated using a variety of approaches. In this study, we assess changes annual and seasonal flow characteristics based on probabilistic representation runoff at daily time scale. The pattern is constructed by determining quantiles from marginal distributions flows for each day within year. By applying Fourier transformation statistics partial series, obtain smooth periodical functions distribution parameters over year consequently quantiles. main findings comparison dry, average, wet hydrologic condition zones as defined selected probabilities. This analysis was conducted ten catchments Serbia considering between two 30-year nonoverlapping periods, 1961–1990 1991–2020. It found that relative change volume most pronounced extreme dry zone winter season (−33% to 34%). shift largest average zones, ranging −11 12 days. applied methodology not only applicable detection change, but could also be used operational hydrology studies via drought indices such Standardized Streamflow Index.