The Lagged Impact of Autumn Surface Temperature Conditions on the Wintertime Beaufort High

The Arctic has recently been undergoing a period of rapid warming, resulting in important changes to the sea ice cover as well as to the patterns of atmospheric circulation. During the winter of 2017, the Beaufort High collapsed as a result of the anomalous propagation of cyclones westward from the eastern Arctic. It has been suggested that warm conditions during the autumn of 2016 contributed to the winter collapse by limiting ice growth over the Barents Sea that provided an additional energy source for North Atlantic cyclones allowing them to propagate farther into the western Arctic. We explore this hypothesis through the application of seasonally lagged multivariate empirical orthogonal functions (MEOFs). The MEOFs were calculated for the Arctic region from the ERA5 reanalysis and the PIOMAS data for the period 1979-2020. The leading seasonally lagged MEOF suggests that a positive relationship exists between autumn SATs and the Arctic Oscillation (AO) during the following winter. A complementary relationship is found for autumn sea ice concentration and thickness anomalies during the winter. These results suggest that a seasonally lagged link exists between surface conditions in the autumn and Arctic cyclone activity during the following winter that can modulate the intensity of the Beaufort High. The implications of this link on the Arctic climate will be discussed.