Synoptic activity associated with sea ice variability in the Arctic

Abstract

Relationships between synoptic activity and sea ice variability in the Arctic are studied using self-organizing maps (SOMs) to categorize observed weather patterns over the 1979–2013 period. The European Centre for Medium-Range Weather Forecasts Re-Analysis Interim provides the daily averaged sea level pressures from which the SOMs are computed. Time series of frequencies and durations of synoptic weather patterns are correlated with two sea ice metrics, Fram Strait ice outflow and year-to-year changes in September pan-Arctic sea ice extent. When compared to climate indices commonly used to predict sea ice, the Arctic Oscillation, North Atlantic Oscillation, and Arctic Dipole, some SOM patterns correlate as or more strongly with sea ice metrics. For example, Beaufort High synoptic patterns are increasing in frequency in spring and their summer frequencies are associated with ice loss. Arctic high-pressure patterns are linked to ice loss through pressure gradients conducive to ice export. The phase lags between the SOM occurrences and sea ice variability offer the potential for augmentation of other approaches to seasonal sea ice prediction.