Wintertime Arctic Oscillation and Formation of River Spring Floods in the Barents Sea Basin

Results from the research on the influence of the wintertime (December-February) Arctic Oscillation (AO) on the spring floods of the North European Russia rivers of Onega, Northern Dvina, Mezen', and Pechora flowing into the White and Barents seas are presented. Composites of the river water discharges from 1930-2014 constructed in accordance with the wintertime AO index above the upper and below the lower quartiles are analyzed. Statistically significant relationships between the dates and intensity of the river spring floods in the Barents Sea basin and the wintertime AO are shown. For all the analyzed rivers, April water runoff preceded by the winters of the AO positive phase significantly increases and by more than twice exceeds that preceded by the winters of the AO negative phase, with the significant runoff increase persisting into May for the Mezen' and Pechora rivers. The earlier and more intensive floods are caused by the earlier spring warming after the winters of the positive AO phase and larger snow accumulation during these winters as compared to the winters of the negative AO phase.