I would like to thank both reviewers for their constructive comments on this manuscript and also the authors for posting their response to the reviewers’ comments.

The manuscript documents the application of a tool for comparing the depth of isochrones identified by ice-penetrating radar with output from ice sheet model simulations, thus testing the accuracy of the model simulations. The approach is highly novel and will be an important tool for evaluating model capability as the database of radar isochrones continues to grow.

Both reviewers are supportive of the study but raise a number of points, in particular, requesting additional information on the methods used and a clearer structure when documenting the results and discussing the implications. Individually, the reviewers also raise a number of additional technical points that require clarification. The authors provide an extensive response to the reviewers’ comments, but I encourage them to check that all points are addressed, any edits are smoothly incorporated into the text, and all features shown on the figures are identified in the legend or caption.

Overall, both reviews are positive and my decision is that the article is suitable for publication subject to revisions. I invite the authors to submit a revised version of the manuscript that addresses all points raised during the preliminary review process.

Kind regards,
Pippa Whitehouse

Dear authors,

Thank you for your clear responses to the issues raised in relation to the previous version of the article and for promptly submitting a revised version. A number of minor points still require clarification, primarily in relation to the figures, these are detailed below. The article may be considered to be accepted for publication once these technical issues are addressed. This is a highly novel piece of work that makes an important contribution to the validation of ice sheet model output. Thank you for submitting to The Cryosphere!

Kind regards,
Pippa Whitehouse (Editor)

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Technical Issues:

Figure 1, top left plot: I think that ice surface elevation is plotted here, please clarify in the caption and consider including a colour scale

Figure 4: please explain what the black circles are on plots B) and C) and include some indication of scale on all plots, e.g. by adding units to the axes

Figure 6: please include units (of time) on the x-axis of A) and correct the values on the x-axis of B)

Figure 8: the caption states that this figure relates to transect DC-X57; is this the same as transect X57a mentioned in the caption to Figure 7? Check that consistent names are used for all transects

Figure 9: I could not find any information, e.g. on a map, to indicate which end of the DC-Y77 transect is regarded as 0 km and which end is 100 km. The x-axis for the upper plot is not labelled: I suspect that both transects are 100 km long, but this should be stated, or both sets of x-axes labelled. In the caption, the black/grey lines at the bed are defined twice.

Line 364: isotope -> isochrone