Clearer sky over possible melt pond area at roughly 85.3N 96.5E northern laptev/cab. Shown here using worldview terra modis cr367 and unihamburg amsr2uhh, may 25-27
Do you think these are really melt ponds?
On the one hand, Terra 3-6-7 does detect liquid vs. frozen water (https://earthdata.nasa.gov/faq/worldview-snapshots-faq#modis-367). But on the other hand, the dark shapes look to me more like some kind of cloud, rather than ice topography. They also seem in places to overlap fractures, which doesn't make sense (but may be illusory) (att). They also don't show up on 7-2-1 (att).
If they are indeed melt ponds, they are very extensive (att).
They may not be melt ponds, but to my (admittedly limited) understanding, they very probably do indicate either wet ice or partially melted snow (e.g. the kind that has formed an irregular surface crust, which increases absorption and traps warmth beneath it, causing a (perhaps) saltier layer beneath it to melt from the inside out)
Clouds always show up white, or at least yellow, on the 3-6-7 image. The only time I ever see a darker orange or red which is not indicating some kind of surface absorption is in the shadow of partial cloud cover in the immediate vicinity.
As to the shape and placement of the darker area - One might speculate on any number of complex scenarios, any one of which might be entirely plausible and completely wrong. Or, for that matter, utterly incredible, yet in fact correct.
That's what makes this whole subject so fascinating and frustrating; The laws of chemistry and physics apply, of course, but the nature of arctic ice is such that, even where it appears uniform, every square meter is the product of a unique summation of past local conditions.
Perhaps the darker swath is just an area that was preconditioned to melt before the rest, because the sun was shining on it through a gap in the cloud cover a week ago?
Perhaps the melting was enhanced in the vicinity of the fissures was due to the surface snow around them being swept into the water, leaving a bare ice surface with higher salinity and lower albedo?
Either is possible, and one might spend a year researching the question and not come up with a definitive answer, because the most significant factor may be one you don't know about.
One thing that does seem clear is that as the average thickness, age, and floe size decrease, and the mobility increases (as they have all been in recent years), the starting conditions become more complex, and the future harder to model with any confidence.