Analysis of a link between fall Arctic sea ice concentration and atmospheric patterns in the following winter.

The impact of anomalous fall Arctic sea ice concentrations (SICs) on atmospheric patterns in the following winter is revisited by analysing results for two time periods: the most recent, satellite-era period (1979-2010) and a longer time-period (1950-2010). On the basis of September SICs for each time-period, an index was constructed which was used to identify anomalous high/low SIC years for both the original, as well as for the linearly detrended sea ice index. Identified years were then used to derive composites for the following winter's monthly atmospheric variables. Mid-troposphere geopotential height composites for winter months are in general reminiscent of the North Atlantic Oscillation pattern with high latitude maximum shifted towards the Barents Sea. Also, lower troposphere temperatures indicate the presence of cooler conditions over the continents during low SIC years. However, differences in the composite patterns are significant only for areas with limited spatial extent. While suggested pathways in previously published studies seem reasonable, our results show that these findings are not yet robust enough from a statistical significance perspective. More data (e.g. provided by longer, climate-quality reanalysis datasets) are needed before conclusions of impacts and feedbacks can be drawn with certainty. [ABSTRACT FROM AUTHOR]