Basal control of supraglacial meltwater catchments  on the Greenland Ice Sheet

Crozier, Josh; Karlstrom, Leif; Yang, Kang

doi:https://doi.org/10.5194/tc-12-3383-2018

Articles | Volume 12, issue 10

https://doi.org/10.5194/tc-12-3383-2018

© Author(s) 2018. This work is distributed under
the Creative Commons Attribution 4.0 License.

https://doi.org/10.5194/tc-12-3383-2018

© Author(s) 2018. This work is distributed under
the Creative Commons Attribution 4.0 License.

Articles | Volume 12, issue 10

Research article

|

29 Oct 2018

Research article |

| 29 Oct 2018

Basal control of supraglacial meltwater catchments on the Greenland Ice Sheet

Josh Crozier, Leif Karlstrom, and Kang Yang

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Final revised paper (published on 29 Oct 2018)
Supplement to the final revised paper
Preprint (discussion started on 17 May 2018)

Interactive discussion

Status: closed

AC: Author comment | RC: Referee comment | SC: Short comment | EC: Editor comment

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- Supplement

RC1: 'Review of Crozier et al. - Basal control of supraglacial meltwater catchments on the Greenland Ice Sheet', Anonymous Referee #1, 14 Jun 2018
RC2: 'Review: Basal control of supraglacial meltwater catchments on the Greenland Ice Sheet', Anonymous Referee #2, 05 Jul 2018
AC1: 'Response to Reviews', Josh Crozier, 22 Jul 2018

Peer-review completion

AR: Author's response | RR: Referee report | ED: Editor decision

AR by Josh Crozier on behalf of the Authors (27 Aug 2018) Author's response Manuscript

ED: Referee Nomination & Report Request started (13 Sep 2018) by Carlos Martin

RR by Anna Grau Galofre (29 Sep 2018)

RR by Anonymous Referee #2 (03 Oct 2018)

Suggestions for revision or reasons for rejection

This manuscript is remarkably improved and approaching publication readiness, in my opinion. Overhaul of the figures has greatly improved the clarity of the paper, and the reorganizing and re-positioning of text has resulted in a more balanced manuscript in terms of methods, results, and discussions. The addition of new results with respect to fluvial incision has also provided a useful complement to the basal transfer component.

I am lukewarm on the results and conclusions regarding IDC density (Figure 11). Future changes in IDC density become one of the primary conclusions of the work, yet the IDC number density is not robust to changes in the parameter space explored here. Further explanation, at least, is needed (see specific comment below).

A short list of particular comments follows. I am confident the authors can address these remaining critiques without many additional substantial changes to the work and presentation.

P8 L13-21 This paragraph makes the role of C* and the authors' decision path on C0* versus C* unclear. The use of 3 different terms, C0, C*, and C0*, if ultimately the chosen slip ratio is spatially constant, could probably be simplified.

P9 L24-33 The descriptions in this paragraph (description of Figure 7) would benefit from being better anchored to separate the methods used for Figure 7b from those used for Figure 7c. Could the 1D and 2D DFTs be given separate paragraphs in 2.3.2, more descriptive and separate captions in Figure 7c, and some emphasis in this paragraph that they are independent of the transfer function result (Figure 7a) to which they are being compared.

P14 L11-19 It would benefit to step through each panel of Figure 7 here.

Figure 7 - x axes are missing label and scale.

Figure 8 / P14 L28 What is the mean misfit in R1?

P14 L30 "unaccounted for physics" is a poor catch-all; what do you mean apart from the linear rheology that you already described? Revise or remove

P17 L4 Some extra words in here

P17 L5-16 / Figure 11 It is strange that any change (increase / decrease) in any of the 4 parameters causes an increase in the number of topographic basins, and makes me question the robustness of this particular analysis. Why is it that the base-case parameters chosen occupy a local minimum in IDC number density? This number density does agree with observations (Figure 11a), but the controls on IDC density are not well illuminated by this set of results.

P19 L2-3 Rephrase this sentence to make it clear that bed topography is the dominant influence at this scale, and fluvial erosion is secondary.

P19 L11-12 Suggest adding "...IDC scales, as our results suggest, then supraglacial stream incision..."

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ED: Publish subject to minor revisions (review by editor) (05 Oct 2018) by Carlos Martin

AR by Josh Crozier on behalf of the Authors (13 Oct 2018) Author's response Manuscript

ED: Publish as is (15 Oct 2018) by Carlos Martin

AR by Josh Crozier on behalf of the Authors (16 Oct 2018) Author's response Manuscript

Short summary

Understanding ice sheet surface meltwater routing is important for modeling and predicting ice sheet evolution. We determined that bed topography underlying the Greenland Ice Sheet is the primary influence on 1–10 km scale ice surface topography, and on drainage-basin-scale surface meltwater routing. We provide a simple means of predicting the response of surface meltwater routing to changing ice flow conditions and explore the implications of this for subglacial hydrology.