Dear Authors,

Thanks for the thorough revision of your paper and for taking into account or answering to the reviewer’s comments. Before final acceptance, I feel that some points still need to be addressed. They are listed below and in the yellow marked PDF attached. In particular, as you are probably aware, a new study has been published in the Journal of Glaciology (Zhou et al. 2017), on a highly similar topic. In my view, it does not affect the relevance/importance of your paper but you need to reference this paper and alter your text accordingly (not anymore "the first time").

To speed-up the review process, please attach to your revised manuscript a cover letter detailing the changes you made in response to my comments. Make sure this rebuttal letter makes a clear distinction between these comments, your responses and the changes you made to the manuscript.

Supplement. Table S3.
"Dates ASTER DTMs used" --> "Dates ASTER DTMs"
"(wighted mean" --> "(Weighted mean)"

Your response letter to the referees
P8, Fig. 3 "also show the total change from 1973-2009". If there is an added value to include the 1973-2009 elevation change you should add it. And I think there is definitively one. Indeed, this point makes me think that you need to clearly state earlier in the manuscript that the correction for penetration has been applied as a mean average (right? the mean value from Kaab et al. [2012]). If I understood correctly, you did not correct for variations of penetration as a function of altitude. Should be clearly stated. Then, this is a good reason to show the 1973-2009 dh value in Figure 3 because the values for subperiods including SRTM may be slightly biased because of higher penetration at high elevation than in the lower part.

Best regards,

Etienne Berthier

Reference

ZHOU, Y., LI, Z. and LI, J.: Slight glacier mass loss in the Karakoram region during the 1970s to 2000 revealed by KH-9 images and SRTM DEM, Journal of Glaciology, 1–12, doi:10.1017/jog.2016.142, 2017.

Dear Authors,

Thanks for the swift revision of your paper. I think most issues are now resolved/clarified.
However, during this last revision, you included some new statements that need to be demonstrated if they were to be retained in the final TC paper. Currently I do not think they are supported by the data, at least as presented in the paper.

Point 1
8.20. “It is therefore important to cover the entire surge cycle of surge-type glaciers in order to have valid estimates of their mass budgets.” I am not sure this is the best formulation. One can have a reliable estimate of the glacier-wide mass balance even if only the active/quiescent part of the surge cycle is observed. The mass balance will only be representative of this specific period, not the whole surge cycle. Do the authors want to imply here that the mass balance could be different depending on the phase of surge cycle? Do they have some data and physical processes to back up this possibility? (could be that a more crevassed glacier surface after the active phase is more prone to melt or that due to the advance of the glacier beyond the earlier front during the active phase an overall lowering of the hypsometry is observed and thus stronger melt can occur…).

The reservations expressed above can also be made concerning two new sentences in the conclusion. “Especially surge-type glaciers show different elevation change characteristics and more negative mass budgets in the second period. During a surge, ice is transported rapidly from an upper reservoir zone to the ablation region and is prone to melt at the lower elevations.” First, from Table1, the mass budgets for the two categories (surge-type/non surge-type) are not statistically different (error bounds). Then your second sentence seems to understate that the mass budget would be more negative during the active phase than during the quiescent phase but in table 1 you did not discriminate “surge-type glaciers” that were active (surging) and those that were quiescent. And how can one isolate the effect on the mass balance of the climate/stage in the surge cycle.

Point 2
Title: The mass budget of these glaciers is in balance (or nearly). However, given their strongly unstable dynamics (e.g., surge) can you really state that the “glaciers are balanced”? The same apply to L13 of the abstract.

To speed-up the review process, please attach to your revised manuscript a cover letter detailing the changes you made in response to my comments. Make sure this rebuttal letter makes a clear distinction between these comments, your responses and the changes you made to the manuscript.

Best regards,

Etienne Berthier

Dear Authors

Thanks for the revision. The revised text (in particular the conclusion) now better reflect the main findings.

Technical correction : avoid repetition of "a short" P8 L20.

Congratulation and thanks for choosing TC,

Etienne Berthier