The paper is now essentially ready for publication. There are a few minor suggestions and one overlooked item from the reviewers comments that require attention, hence the decision “publish subject to technical corrections”.

To start with the latter, reviewer 3 requested identification of the interesting episodes discussed in the text with arrows for Figure 4. You replied that this was done, but I don’t see those markings in my copy (only Figure 5 has those markings). Please consider to add those in the final version.

Reviewer 2 commented that “ïn some of the discussions it was easy to get lost in the details”. I have to agree with this sentiment, but this would really require a lot of editing which I am not expecting you to undertake. I will however list a few comments and possible corrections, referring to the final version (4?) of the manuscript. I mention this version because the page/line numbering has of course changed between the original and final version. That makes it difficult for your editor to trace what was modified where in the manuscript. For future manuscripts I do recommend that you submit revised versions of a manuscript clearly marking where the text was modified (for instance by showing old vs new text in color); this should be easy to remove before submitting your final manuscript.

Comments/corrections/questions:
-If I understand it well, “Concordia” and “DC” refer to the same data. The arbitrary use of both terms seems arbitrary and could be confusing. I recommend to use one descriptor only (DC, which is shorter)
-I (nor the referees) have not checked all your quoted references. I assume you have double checked them all yourself!
P5/L15 “missed” -> “missing”
P6/L7 what do you mean with “concerns”? Maybe “is happening over”? Requires some better formulation
P6/L17 “they have” -> delete “have”
P6/L18 “only in” -> “only on”
P6/L21 concerning Figure 5, the labeling is wrong: “black” pertains to O3, “red” pertains to trajectories
P7/L16 I don’t understand “even”, do you mean “even not considering the loss reactions”? Furthermore, I don’t understand how I can see from Fig 7 (which says it is ~0.3 ppb/hour) that the daily net production rate reaches 4 ppb/day.
P9/L21 “may be related to dilution from” -> “may be caused by dilution due to”
P9/L22 “It also explains”-> “It also would explain”
P9/L23 “that may reach 4 ppbv over 24 hours is never reached”-> “never reaches 4 ppbv over 24 hours”. I am still confused about this statement; it does seem to be at odds with P7/L16 (see above), so a little more thought might have to go in these two statements.
P10/L7 “during that time contained” -> “during that time, contained“
P10/L8 “margin region” -> “margin regions” or “the margin region”
P11/L15 “The cause of”-> “The reason for” (?)
P11/L20 “the higher resulting near surface ozone values”-> “the higher ozone values near the surface”
P12/L15 what do you mean with “inversion winds”. I don’t believe this term exists in English, I presume you mean “wind shear” or “reversion of the wind direction”
P13/L16 to explain the 5 ppbv (ozone, which is of course an ozone depletion event) you need a reference for the bromine chemistry here (Simpson et al., ACP 2007?)
P14/L3 I am bothered by the “all sites except HA”, if in reality it is not statistically significant except for DDU and SP, as you mention on the next line. This seems too strong a statement
P14/L18 “change reversal” ? Maybe “the reversal of the trend” ?
P14/28 I don’t buy this argument. The R2 for the October data has dropped from 0.53 to 0.098 which to me indicates that it is in fact changing, but just not as fast, and the trend has not complete reversed yet. Seems reasonable?
P15/L8 “works” -> “work” or “studies”
P15/l14 why were the McMurdo data not used, assuming they are available?
P15/L27 “for instance”-> delete
Jan Bottenheim