is there a warm current sneaking it's way along the coast?
FishOwater has been on a roll lately with some great posts, calling our attention to the SSW (sudden stratospheric warming) event of 12 Feb 18 aka day 43 and its consequences for subsequent weather patterns. I looked to see whether that date showed up as a breakpoint on Ascat sea ice motion, UH AMSR2 sea ice concentration, GFS winds, or OSI-SAF sea ice motion.
Sure enough, day 43 was the start of the remarkable North Greenland retro-event that backed already exported Fram ice up across the flux gate, along with creating a major lift-off and associated open water.
Ice export eventually returned to its previous pattern until early June when the semi circumpolar drift weather pattern drifted into the indeterminacy that continues until today. Note
no transpolar drift has occurred in recent years, ie don't trust old textbooks, look at actual ice motion, read current journals:
Collapse of the 2017 Winter Beaufort High: A Response to Thinning Sea Ice?
March 2018 Geophysical Research Letters 45(6)
DOI: 10.1002/2017GL076446
Now this was one of these low pressure systems that not infrequently barrel up into the Arctic Ocean between Svalbard and Greenland. So in terms of SSW, was this coincidental, correlated, or causal?
Oceanographic work by A Muenchow and others has indicated a returning path for Atlantic Waters along the Lomonosov Ridge and out the Nares year-round at depth. This route takes several years to complete so even if somehow now affecting north Greenland surface waters, it wouldn't be tied to the current intrusion.
Thus FishOwater's proposal for unprecedented Atlantic Water upwelling and westward dispersal to this region, despite its dire implications for the future of the CAB, is more attractive, though it remains to be seen how it will play out over coming weeks.
Some forums are still claiming that the SV-FJL-SZ retreat is eating into MYI CAB ice.
Wrong. I've explained
40-50 times this year that this is not the case. Even now, retreat is only processing the long tongue of FYI that was extruded from the Kara (and Laptev), see the Ascat mp4 below.
It is more accurate to say, as Rox and others do up-forum, the melt season mostly just undoes freeze season, with both operate primarily on ice peripheral to the core CAB. The CAB surely undergoes thickening and thinning over the year but mostly we cannot observe it. Hence the immense interest in the still-unfolding west Lincoln Sea event.
Note too
not one snowflake from the Arctic basin has exited via the CAA garlic press this season. The aforementioned summer weather is not up to the job.
As shown earlier, a huge thick floe of MYI pushed down one of the minor channels last summer completely blocked the NW Passage above the Lougheed Island pinch-point.The Northwest Passages are mostly melting in situ, with more southerly ice breaking off and being brought by currents into Baffin Bay as in past years. The M'Clure Strait cork has quieted down and been replaced by lift-off (tracked in recent uniquorm posts).
We have had an atmospheric circulation vortex around Greenland for over 3 months that was brought on by the major stratospheric warming in February. That stratospheric warming was caused by the strongest wave driving event, which drove energy upwards from the troposphere to the top of the stratosphere, on record.
There's more warm salty Atlantic water spinning around the N coast of Greenland that's moving into the waters of the CAA. Brief events where the ice blows off N Greenland cause an increase in surface salinity. Longer events of clockwise winds may well up relatively warm salty water from the 300m Atlantic water layer along the continental shelf. This is serious stuff.
Many of the models we have seen over the years pile up ice along the N shore of Greenland and the CAA as a last resort as the Arctic heads towards blue water, but we are seeing right now the beginning of the collapse of that last resort. The remaining ice is thin and shattered north of Greenland and into the Lincoln sea. The shattered ice is floating in a matrix of open water.