Connections across seasons in atmospheric circulation and sea ice have long been sought to advance seasonal prediction. This study presents a link between the springtime stratosphere and Arctic sea ice in summer through autumn. The polar stratospheric vortex dominates the winter stratosphere before breaking down each spring, called the stratospheric final warming, as solar radiation returns to the pole. Inter-annual variability of this breakdown is dynamically driven, leading to different

more »

... time tropospheric and surface circulation patterns. To examine the different impacts of delayed and early final warmings, a multi-model composite was generated from selected CMIP5 models. Additionally, regressions were performed on the JRA-55 reanalysis against an index of springtime polar vortex strength. In both the multi-model composites and reanalysis regressions, significant anomalies in sea ice thickness persist several months following an anomalous timing of the final warming. A later final warming or stronger springtime polar stratospheric vortex leads to negative sea ice thickness anomalies in the East Siberian Sea and positive anomalies in the Beaufort Sea in comparison with an earlier final warming or weaker polar vortex. The spring polar stratospheric vortex is related to spring polar surface circulation patterns. The winds associated with this pattern induce anomalous sea ice motion, moving ice from the East Siberian Sea towards the Beaufort Sea. Reduced sea ice in the East Siberian Sea is linked to anomalous warmth over this region in autumn. Our results suggest that the timing of the stratospheric final warming exerts an influence on the tropospheric circulation and sea ice through autumn which has implications for seasonal climate prediction.