Linkages Between Arctic Summer Circulation Regimes and Regional Sea Ice Anomalies: Drivers of Retreat?

Studies of linkages between summer atmospheric circulation patterns and the downward trend in annual Arctic sea ice minimum have suggested systematic relationships between low sea ice years and the Arctic Dipole pattern (anticyclonic over the Canada Basin and Greenland and cyclonic over the Eurasian coastal seas; Wu et al. 2006). The Arctic Dipole pattern, which emerges as the third EOF of Arctic circulation, represents a meridional flow that promotes ice export through Fram Strait and a strong feedback to Arctic tropospheric warming. While this first order relationship has been strong, particularly in the last few decades, departures in Arctic sea ice extent from year to year are typically the result of large and often partially compensating regional anomalies, which in turn reflect regional-scale anomalies in atmospheric circulation (Serreze et al. 2015). To allow for a more detailed assessment of regional Arctic sea ice extent anomalies and sectoral circulation variability, we use a Self Organizing Map (SOM) framework that distributes atmospheric circulation regimes into 20 or more types. We focus on the period 1979-2015 for which we have daily sea ice records using the combined Nimbus SMMR and DMSP SSM/I-SSMIS 25 km product. We find that statistically significant relationships between sectoral sea ice retreat are in fact many-to-one, and explore the extent to which these relationships may have been changing over the last three decades.

Serreze, M.C, Stroeve, J., Barrett, A.P., Boisvert McPartland, L., 2015: Summer Atmospheric Circulation Anomalies over the Arctic Ocean and Influences on September Sea Ice Extent: A Cautionary Tale. (in prep). Wu, B., Wang, J. and Walsh, J. E. 2006. Dipole Anomaly in the winter Arctic atmosphere and its association with sea ice motion. J. Climate 19, 210–225.