Been a couple of interesting readings in the last few days on the ITP95 charts, the buoy Nth of Fram strait co-located with 2017B. Shes basically drifted due east 10 km in the last 3 days since the 24th July update to now 84.9N 8.76E on the 27th. Inset on the sentinel hi res image are 20x20km worldview tiles of the exact spot on the 27th, small one unadulterated and the larger with as much detail as I could wring out of the fog. The big Sentinel image is as close as I could get a clear shot, from the 25th and goes to 83 nth and 7 east. Should be pretty similar Ice conditions I would think.
I've put a frozen pic of what I commented on a few days ago here too for those who seem to really want it.
Anyway. Seems to have been an upwelling of low oxygen water from 1km+ depth. And perhaps a small rise in the salinity associated. Perhaps a slight temperature boost towards the surface and fattening of the warm strata, but difficult to say it was a contributor.
Then soon after there's a big down spike in the temperature and salinity contours, particularly at about 150 to 200m. About a 30m downwards excursion.
Are the two associated? Is this an ekman pumping vortex, or some other phenomenon? Has a plume of more saline water risen, perhaps methane, or hydrothermally driven, then cooled and descended.
I've been pondering if another mixing factor could come into play, around a certain floe diameter, perhaps optimised in the couple of hundred meters to a km range, when open water is surrounding floes like these. If the bottom is salty, and melts at -1.8 or so as with recently formed ice that's concentrated its brine at the bottom of the floe. And the water around has risen in temp a bit due to a bit of insolation and air interaction. Perhaps a bit of fresher warmer surface melt adding to it, aided by the humidity condensing on floes thin enough to be conducting the energy to their base which is pegged by salinity to below zero.
Wouldn't there be a tendency for water to sink under the flow, and draw in more water from the periphery to replace it? Is this plausibly a significant mixing process in a poorly seasoned FYI ocean state like we now have? This floe has registered twice as much bottom melt as top melt.
I guess that the open water areas being in the order of a km there is plenty of opportunity for wind induced surface movement, chop, and turbulence anyway.