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I have a question for anyone here regarding the importance of continental snow levels in evaluating the sea ice situation. My simple interpretation is that they are an indicator of continental albedo. Lower continental albedo means the land can heat up more and has increased potential to contribute heat to the ice via warm air advection (WAA). Do others see it the same way or is their more to the connection between continental snow and sea ice?
Oh yes, there is more. Much, much more.
Imagine you try to hit a nail with a hammer, but hit your finger instead. Then you ask: what's the importance of my finger being hit by this hammer? Is it that the nail nearby was a bit shaken by the impact of this hammer hit - by the shockwave spreading through my finger and into the board and through it, into the nail? Why, certainly, there is that. But much more important thing is - IT HURTS!!!
Right?
Well, same deal with snow cover going away that much earlier. The hammer is sunlight. And the importance of this sunlight wiping away all that snow - is that that same sunlight also hammers the sea ice. Directly. Massively. It melts it. If the snow is gone, then we now it's mainly Sun to blame.
Why look at snow and not at the ice? For the time being - this part of melt season - it is simply so much easier to see the impact exactly on land, because snow is white, while land under it is dark. While ice under snow which was over that ice - is not dark, it's white.
By estimating snow cover in areas directly adjucent to ice-covered areas especially vulnerable to melt during this time of melt season (regarding temperatures, how high sun is over horizon for how long every day, thickness, etc) - first and foremost we can see, with high degree of confidence, how much melt is likely to be happening to snow cover of sea ice and sea ice itself. Everything else - is secondary.
Secondary effects can pile up longer-term, of course, and yes, heat content of air masses is one such thing. Warmer and earlier river runoff is yet another. Possible regional methane release, already mentioned above, is also one - by the way its GWP over 1 year is ~120 of CO2; over few weeks / months? Hundreds times higher than CO2, so any serious release is no joke. Yet another consequence is that further insolation will likely heat up that dark soil well above 0C, - while areas still covered by (by then melting) sea ice will remain near 0C, thus often helping to intensify winds, with further consequences for the ice.
But again, all those are relatively small deal. Insolation is "the" thing to be looking for in June (and near it). Particularly this year, with cleaner air - which intensifies things. To the point it, kind of, "HURTS!!!".
<Great post, removed one word. O>
<It is in my country's culture to keep such words in when emotionally fit, despite obscenity. Apologies... F.T.>