On ice motion gradients in the Arctic

In this study we examine ice motion gradients as an extension to previous studies of wind gradient variability from the stratosphere to the lower troposphere in the Arctic. Examined in particular are distinctive patterns in seasonal ice relative vorticity, divergence, strain, and Okubo-Weiss fields for the Arctic region from 1979 - 2010. Results from this analysis show distinct spatial patterns in seasonal means for ice relative vorticity and ice divergence in Fram Strait and the Beaufort Sea region during winter, spring and fall. Trends in divergence during winter show positive values in a region extending from the northern Chukchi Sea to the western Beaufort Sea, while trends in square of strain depict a reduction in straining mechanisms in the Arctic. Moreover, trends in the Okubo-Weiss fields parallel trends in ice divergence in winter and strain in summer. Patterns in all ice motion gradient trends resemble those of sea ice concentration anomalies in the western Arctic in fall. The results from this analysis will assist in projections of sea ice dynamics and in assessing free ice drift conditions within an increasingly mobile ice cover in the Arctic, with implications for transportation, shipping, and attendant policies dedicated to Arctic economic and environmental sustainability.