I have identified something in climate indices which may be related to the previously noticed sudden shift in Northern Hemisphere Snowcover: it appears to occur at about the same time as a sudden, large spike in the Arctic Oscillation. I have not yet verified if this change preceded or followed the change in snow cover (and I can indeed imagine snow/ice cover forcing changes in circulation, this probably played a major role in the glaciations) although the reverse is surely true as these circulation patterns are linked to weather systems that deposit snow in the first place. Anyway, as always I examine the data with a careful, curious eye for details others might miss, to examine the implications of these findings for various hypotheses. So far, I have no idea what to make of these findings, but readers feel free to speculate wildly!
The AO data from here:
Are the average of the eleven and thirteen month centered averages. I realize this is slightly different from my method of averaging the Snow Cover data, which is part of why I have not yet determined the exact relationship between these two series. More later, maybe!