Association between modes of variability of January Northern Hemisphere snow cover and circulation

An Empirical Orthogonal Function (EOF) analysis has been applied to NOAA/NESDIS snow concentration data. The major modes of variability in January Northern Hemisphere snow concentration have been extracted and analysed. The analysis was completed separately over Eurasia and North America. Strong, coherent patterns were found for each of the first three EOFs that were analysed over both continents. Over Eurasia the first EOF showed much of Europe as well as western and central Asia in phase but eastern Asia of the opposite phase although the signal was somewhat weaker. North America had a very similar first EOF with a large positive anomaly centered over Montana reaching loadings of over 0.8. East of the Great Lakes, the anomaly changes sign, although again, its magnitude is much smaller.