Dear authors,

I have now received two reports on your revised manuscript. Overall, both referees consistently remain critical, and consider that the issues raised in their first reviews have only been partially addressed, if at all. At this point, the main reason for not rejecting the paper is the richness and potential usefulness of the continental scale dataset presented. However, for the paper to be published in TC, thorough improvements of the analyses, discussions, and presentation quality are in order. In particular, as pointed out by both referees, the statistical significance of the presented trends shall be assessed much more carefully, acknowledging potential correlations in the times series. The data sources and methodolody need to be presented with greater details. The English language also requires considerable improvement, probably through editing by a native English speaker, as some parts of the paper are really hard to follow (notably the newly-revised sections). Please consider resubmitting a revised manuscript only if you feel that you can satisfactorily respond and address all the different points raised by the reviewers.

Best regards,
Guillaume Chambon / TC Topical Editor

Dear authors,

Thank you for submitting a new version of your article. It appears to me that several of the issues raised by the referees have now been convincingly addressed, and that this new revision might be positively appreciated by them. However, there are still a few improvements needed before I could send this revised version back to the referees:

1/Even though the English language was globally improved, numerous sentences / sections throughout the manuscript remain poorly phrased and hard to follow, in particular (but not only) in the newly-revised parts. Overall, the language still does not meet the standards expected for an international scientific publication. Therefore, I urge you to have the manuscript proofread and revised by an native English speaker or a professional English editing service.

2/ The new appendix concerning serial correlation analysis should be appended at the end of the manuscript, rather than provided as a supplementary material. In this appendix, please carefully define all used quantities and explain how they are derived (e.g.: d_1 and d_u). Also: indicate units in tables whenever necessary.

3/ As repeatedly mentioned by the referees, the discussion remains too short relative to the overall length of the manuscript. Why did you chose to delete the part concerning topographical effects? The newly-added paragraph concerning comparisons with modelling studies remains very brief, and could certainly be expanded further. In particular, you should better explain why you put a special focus on high-elevation and forested areas in your last sentence. Similarly, the implications of your results would need to be discussed in a broader context, not only limited to permafrost issues. Overall, the goal in this discussion would be to better demonstrate the significance of your study in the frame of all the works currently going on in relation to the effects of climate change on the cryosphere.

I regard these further improvements as mandatory before requesting the services of the referees yet another time. Hence, please carefully consider these issues and submit a new version of your paper appropriately revised along these lines.

Best regards,
Guillaume Chambon / TC Topical Editor.

Dear authors,

Your revised manuscript has undergone a new round of reviews.

Referee #1, who already reviewed the previous versions of the paper, considers that his comments have now been addressed to a satisfactory degree. He nevertheless points out a number of minor issues, mostly technical in nature, that still need to resolved in the manuscript.

Referee #3, who did not participate to the previous reviewing rounds, is more critical and identifies several weaknesses and flaws that lead him to recommend rejection of the paper. Given the amount of effort already invested by you and the referees in the improvement of this paper, I give you the opportunity to respond to his comments and modify your manuscript appropriately. Please carefully address all the methodological issues that he raises. Consider also further editing the introduction and discussion sections, in particular, to better relate your work with the current "hot" scientific questions highlighted by the referee.

I hope that this will be the last revision of the paper, and am confident that you will finally submit a manuscript that reaches the standards required for publication in The Cryosphere.

Best regards,
Guillaume Chambon / TC Topical Editor.

Dear authors,

I did not send the new revised version of the paper to the referees, but assessed it myself. As a non-specialist of the topic, I certainly appreciated the reorganization of the introduction and discussion sections, which significantly improved the paper. Yet, I consider that the overall quality of the manuscript still remains insufficient for publication in TC. In numerous places, and notably in the newly-added paragraphs, the wording and explanations need further clarification and/or editing. I listed a number of issues, mostly technical in nature, in the attached pdf file. Addressing these different issues is required not only to meet the high-level publication standard of TC, but also to produce a paper that does full justice to your exceptional dataset. Feel free to ask me directly by email if you have any question concerning my comments.

Best regards,
Guillaume Chambon / TC Topical Editor.
guillaume.chambon@irstea.fr

Dear authors,

Thank you for these new revisions that certainly contributed to improve the clarity and readability of the manuscript. You can now consider your paper as provisionally accepted for publication in TC. I do nevertheless have a few additional comments and suggestions (see attached file) that you may want to consider prior to submitting the final version.

Best regards,
Guillaume Chambon / TC Topical Editor