Small historical analysis based on the southern summers from 2002/2003 (19 summers in total) using images from the Modis archive (until summer 2018-2019):
In 12 summers the sea ice in the Pine Island bay in front of the PIG has completely melted (in 7 cases already in October and in 4 cases in November).
In two summers the 3 polynyas, corresponding to the NSM, the centre and the SSM, merged to form a long polynya along the entire front, but no melting of the sea ice in Pine Island Bay.
In 5 summers there was no melting of the sea ice in front of the PIG.
It is remarkable that in the summers from 2003-2004 to 2007-2008 (five summers therefore) there was no melting of the sea ice in front of the PIG and these years correspond to years of powerful CDW and accelerated retreat of the grounding line.
It is thus necessary to be careful, there is a link, more or less strong, between CDW and polynyas, but not between CDW and sea ice melting!
For sea ice, one should rather look for atmospheric conditions and sea surface currents.
For this summer we can say :
That it has snowed a lot and that there hasn't been, in general, a big melting (see attached pictures).
Based on the Sentinel2 images, which are very often very cloudy, one can imagine that in general the weather was often cloudy or very cloudy.
This is unfortunate, but there is no global information on winds and sea currents at the surface.
As far as the polynyas are concerned, the one in front of the NSM was well visible, when it was not filled with the rubbish from a calving, and sporadically the one in the centre when it was not filled with rubbish of NSM origin (there were nevertheless movements of the sea ice, even if very slow), but the one corresponding to the SSM is missing. This can be explained by the presence in the SSM of a dense ice mélange which is much more difficult to melt. Concerning the small polynya in front of the SM between the SWT and the SIS, its origin is due to the fact that the outgoing current corresponding to this SM, because of the retreat of the front line, no longer merges with that corresponding to the SSM and has become independent.
So even from the presence or not of the polynyas is not obvious under these conditions to make diagnostics on the power of the CDW.
In any case the fact that the dense mixture remains close to the SSM is not a valid defense for the PIG, it only slows down the emptying and deepening of the SdDZ. The state of health of the PIG is and remains very bad.
click to enlarge