In terms of the mechanisms restricting ice melt this season, to the extent that they have anything to do with air temperature, a cool Arctic above 80N means an absence of overrunning air from southern latitudes. Every sharp temp spike up there is simply a wind spike — from the south. While warm sea water incursions matter significantly more than air temps when it comes to sea ice melt, air temps do matter. As an example, 2007’s then-record melt could have taken place without a prolonged high-Arctic warming, wind-generated, during the first months of 2006.
Yes, there were other mechanisms at play during the summer of 2007 that even NASA admitted were simply weather. But a really important element of the causality of 2007’s melt was weather that happened more than a year before. That wintertime “heat wave” has never been written about by NSIDC or any other group as a component cause of 2007. The big question is: Why not?
Meanwhile, returning to 2013, a faster-than-average gyre, as has been seen this summer, equals a buffer against warm overrunning air. And, lo and behold, less melting of sea ice.
