Contribution of late spring Eurasian snow cover extent to Canadian winter temperatures

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Abstract

This study examines intercontinental linkages between late spring and early summer Eurasian snow cover extent (SCEss) anomalies and the following winter temperature anomalies over Canada for the 1972–2006 period. The structure of the second interannual mode of Canadian winter temperatures variability captures the SCEss related modulation. The North Atlantic winter atmospheric circulation changes associated with the SCEss, resembling the negative phase of the North Atlantic Oscillation (NAO), suggest a possible pathway for the SCEss influences on the Canadian winter temperatures.

Regression and composite analyses show that the SCEss relate robustly to the Canadian winter climate. Larger-than-normal SCEss is associated with below normal winter temperatures in south-central Canada and above normal temperatures over northeastern Canada. Predictive skill of Canadian winter temperatures based on a cross-validated regression model shows that the SCEss offers the predictive potential over regions of Canada where El Niño-Southern Oscillation (ENSO) related skill is weak or nonexistent. Analysis of winter extreme minimum temperatures, by a non-stationary generalized extreme value model, with the SCEss as a covariate, exhibits statistically significant changes over Canada resembling a pattern similar to that of winter mean temperatures. Wavelet analysis shows significant coherence between the SCEss and the second mode of winter temperature variability in the 8–12-year band. Copyright © 2011 Crown in the right of Canada. Published by John Wiley & Sons, Ltd

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