Interannual surface evolution of an Antarctic blue-ice moraine using  multi-temporal DEMs

Westoby, Matthew J.; Dunning, Stuart A.; Woodward, John; Hein, Andrew S.; Marrero, Shasta M.; Winter, Kate; Sugden, David E.

doi:https://doi.org/10.5194/esurf-4-515-2016

Articles | Volume 4, issue 2

https://doi.org/10.5194/esurf-4-515-2016

© Author(s) 2016. This work is distributed under
the Creative Commons Attribution 3.0 License.

Special issue:

Frontiers in geomorphometry

https://doi.org/10.5194/esurf-4-515-2016

© Author(s) 2016. This work is distributed under
the Creative Commons Attribution 3.0 License.

Articles | Volume 4, issue 2

Research article

|

30 Jun 2016

Research article |

| 30 Jun 2016

Interannual surface evolution of an Antarctic blue-ice moraine using multi-temporal DEMs

Matthew J. Westoby, Stuart A. Dunning, John Woodward, Andrew S. Hein, Shasta M. Marrero, Kate Winter, and David E. Sugden

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Final revised paper (published on 30 Jun 2016)
Preprint (discussion started on 18 Nov 2015)

Interactive discussion

Status: closed

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

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RC C540: 'Comment on "Inter-annual surface evolution of an Antarctic blue-ice moraine using multi-temporal DEMs"', Anonymous Referee #1, 15 Dec 2015
RC C553: 'Review', Anonymous Referee #2, 18 Dec 2015
AC C660: 'Final author response', Matthew Westoby, 05 Feb 2016
EC C661: 'Editor recommendation for re-submission', John K. Hillier, 08 Feb 2016

Peer-review completion

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

AR by Matthew Westoby on behalf of the Authors (09 Feb 2016) Author's response Manuscript

ED: Referee Nomination & Report Request started (19 Feb 2016) by John K. Hillier

RR by Anonymous Referee #2 (26 Feb 2016)

Suggestions for revision or reasons for rejection

The paper has been restructured as requested in the reviews, and is much easier to interpret with the redrawn figures. The discussion of the processes and mechanisms driving the change is, in theory, substantive enough to warrant publication. However, and it is a big however, with the added figure comparing the TLS and SfM data and the production of Figure 4 in colour, serious questions are raised over the use of the two methods to draw conclusions about the geomorphological processes. Firstly the colour scales differ on figures 3 & 5, making it hard to analyse the results in figure 5 in the context of figure 3. On close inspection, the error level is of a similar order to the results that are being presented. There looks to be a systematic bias in the comparison between the TLS and SfM, which I don’t think is adequately explained in the paper. The bias trends from a positive bias in the south, then turning negative towards the north, and show some dependence on the moraine ridges. This puts the results of figure 5c into doubt, in particular the large negative surface lowering in the ice marginal area, and the pattern seen along the moraine ridges. Where there is limited data in the ice marginal area in figure 5d, this signal is not seen.
I would recommend that the authors reinvestigate the difference between the TLS and SfM and revise their analysis on the basis of the robustness of the comparison between the two datasets. Finding that the TLS and SfM don’t produce the same result doesn’t preclude the publication of the paper as it is a useful discussion to be had. I just think the discussion of the geomorphological processes is now not valid in the light of the evidence brought by the greater clarity in Figure 4 and the insertion of Fig. 3.

A small comment on Fig 5: season 2 “end” needs to be labelled properly to help reader interpretation.

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RR by Anonymous Referee #1 (15 Mar 2016)

ED: Reconsider after major revisions (16 Mar 2016) by John K. Hillier

AR by Matthew Westoby on behalf of the Authors (27 Apr 2016) Author's response Manuscript

ED: Referee Nomination & Report Request started (20 May 2016) by John K. Hillier

RR by Anonymous Referee #2 (03 Jun 2016)

ED: Publish subject to technical corrections (06 Jun 2016) by John K. Hillier

ED: Publish subject to technical corrections (06 Jun 2016) by Tom Coulthard (Editor)

AR by Matthew Westoby on behalf of the Authors (15 Jun 2016) Manuscript

Short summary

We quantify the surface evolution of an Antarctic blue-ice moraine complex over 1- and 12-month intervals using repeat terrestrial laser scanning and structure-from-motion photogrammetry. We find net uplift and lateral movement of moraines within a field season (mean uplift ~ 0.10 m) and local surface lowering of a similar magnitude. Net uplift across the site between seasons was 0.07 m. Such data offer new opportunities to understand linkages between surface ablation, ice flow and debris supply within moraines.