Based on the reviews, I recommend this paper be accepted for publication in TC after minor revisions. In addition to addressing the reviewer comments, I have a few suggestions to improve the readability of the paper:

I strongly discourage the extensive use of supplemental material in this case. Supplemental material is best used for material that cannot be put in the main paper (e.g. multimedia) or technical details. As your supplemental figures are relevant to the main results and discussion, the readability of the paper would be improved if this material was included in the main paper instead. This will make your paper more accessible to readers.

Line 85-95 and table 1: What in-situ data are you validating against? This needs to be described and referenced.

Materials and Methods – here you list what data you use, but it’s not clear in what way it is used. E.g. the Argo float data, and eddy data. This section could be improved if you simply state how each of these data sets will be used.

Line 142 – “missing” might imply you had no data, but I think you mean that no chl-a was observed.

Line 157 – If it’s only one float, it’s not a fleet.

Figure S9 – please be clear if this is incident shortwave or absorbed shortwave. Also, please indicate where this data is from in the revised manuscript.

Figure S6 – specify which is Weddell Sea polynya and which is Maud Rise Polynya.

The authors have addressed the reviewer comments, but have not fully addressed the editor’s recommendations on presentation. Therefore, I will make detailed recommendations for changes in presentation to make the manuscript consistent with TC style and standards.

Supplemental material should only be used in very specific circumstances. It cannot be used to illustrate new points. It is intended for items that cannot fit in the main text because of format or size, but should be avoided in other cases. In most cases, the SM figures illustrate new points. In these cases, they MUST be in the main text. In those few cases where the supplement points are already made in the main paper with text and figures (see below with respect to Figure 5, S3 and S4), I still recommend placing in the main text, as there is no reason for a simple figure to be in SM. In this case, an appendix might be reasonable, though I do not see that as necessary here.

These changes will make the paper more readable. The authors should either put all SM figures in the main text, or if not needed to support any points, leave them out altogether.

Figure S1 – Figures should not normally be in the introduction. This presents results similar to what has been previously published (at least with respect to sea ice, to some degree with the ARGO data). If these results are adequately published elsewhere, I recommend it just be cited with no figure if you are citing it in the Introduction. If these are new results, these SHOULD NOT be in the supplemental material, nor in the introduction and should be presented in the Results section with a figure in the main text. This was not commented on by the referees, so I will leave this up to the authors, but I suggest this would be more useful if you just looked at the Weddell Sea rather than the whole Antarctic, and then this could be included in the results.

Figure S2 – These data are useful to understand how close the data are to the study area, and the quality of the relationship with NPP. As this is used to choose the model, it should be in the main text.

Figure S3, S4, and Figure 5: These figures all support the same point. Notably, S4 and 5 show the same data, with Fig 5 just showing detail. I’d combine into a single figure, but it is fine if you want to keep them separate. But as they are presenting evidence for the new point that there is upwelling locally at the MR, they should both be in the main text. Figure S3 isn’t consistent in timing with Figure 5, and since the former is a model and latter data, I wonder if S3 is needed to make your point and should just be excluded. If you retain it, I think it should be discussed a bit more in the main text to explain these differences (and thus, the figure needs to be in the main text).

Figure S6 – again, this is introducing a new point, thus according to journal policy, should be in the main text.

Figure S7 – same reasoning as for S6.

Figure S8 – This figure is pertinent to show the timing of the polynya, so should be in the main text. I’d suggest that since this provides a clear visual of the evolution of the physical setting driving your observations, that this would be most useful as a figure 1 to provide the reader an introduction to the setting.

One final point that should be clarified - The Figure 7 caption indicates the figure is showing incident shortwave radiation, which one would normally interpret as incident downwelling shortwave. The text on line 233 indicate net shortwave (downwelling-upwelling), which would be the absorbed shortwave. I think the figure is showing net. If so, the caption should be fixed