Shifting seasonality of flow regimes across Europe

Europe hosts a diverse range of seasonal flow regimes, but this diversity remains only partially characterized. We use directional statistics to analyze streamflow seasonality across Europe, examining the timing and the temporal concentration of seasonal flow regimes. Geographical differences in seasonality are primarily shaped by climate, but regionally distinct imprints of landscape conditions (e.g. geology) appear. In many catchments, river flow seasonality has changed in recent decades. Seasonality has dampened in most nival flow regimes and increased in most pluvial flow regimes. Shifts in timing tend to be more variable within geographically and physiographically similar regions but can be linked to shifts in climate seasonality.