Self-affine subglacial roughness: consequences for radar scattering and basal water discrimination in northern Greenland

Jordan, Thomas M.; Cooper, Michael A.; Schroeder, Dustin M.; Williams, Christopher N.; Paden, John D.; Siegert, Martin J.; Bamber, Jonathan L.

doi:https://doi.org/10.5194/tc-11-1247-2017

Articles | Volume 11, issue 3

https://doi.org/10.5194/tc-11-1247-2017

© Author(s) 2017. This work is distributed under
the Creative Commons Attribution 3.0 License.

https://doi.org/10.5194/tc-11-1247-2017

© Author(s) 2017. This work is distributed under
the Creative Commons Attribution 3.0 License.

Articles | Volume 11, issue 3

Research article

|

24 May 2017

Research article |

| 24 May 2017

Self-affine subglacial roughness: consequences for radar scattering and basal water discrimination in northern Greenland

Thomas M. Jordan, Michael A. Cooper, Dustin M. Schroeder, Christopher N. Williams, John D. Paden, Martin J. Siegert, and Jonathan L. Bamber

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Final revised paper (published on 24 May 2017)
Preprint (discussion started on 10 Jan 2017)

Interactive discussion

Status: closed

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

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RC1: 'Referee Review', Anonymous Referee #1, 16 Feb 2017
RC2: 'Review of Jordan et al. 2017', Neil Ross, 16 Mar 2017
AC1: 'Author comments to both reviews', Thomas Jordan, 13 Apr 2017

Peer-review completion

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

AR by Thomas Jordan on behalf of the Authors (13 Apr 2017) Author's response Manuscript

ED: Publish subject to technical corrections (21 Apr 2017) by Olaf Eisen

Dear Tom Jordan,

thank you for revising your manuscript following the two reviews. You sufficiently considered their comments and adequately changed the manuscript, which I therefore can accept for publication in TC. However, I ask you for several editorial changes, listed below, before you upload your final version.

Regards,
Olaf Eisen

line 136: delete one “where”
249-251: rewrite last sentence, difficult to understand
281: “glacial” does not fit, I suggest to change to “As RES over ice employs …”
315: scatterer dimensions are …: unclear what the numbers mean, relative dimension of dimension of space (then unit is missing)
334: split sentence: assumes radial isotropy for H and Xi. Since we are …
338: repedition: Paden already cited above where wavelength is first introduced.
378: Unclear where 0.65 is coming from and what it means here: resolution of number of range cells? If resolution, why? Unit missing?
413: (5.2) -> (Sect. 5.2)
460: although it clear that: add “is”
516: 100s km2 -> 100s of km2
685: remove () from citation
Figure 1: last sentence: fix grammar “have … is”. Add after last sentence: by a factor of 10.
Figure 6: title and first sentence in caption: northern Greenland -> north-eastern Greenland
Figure 7: I suggest to use the same scale for y-axes of b, c, d at least, as not only the shape but also the area is important for visual comparison.
Figure 8: Same as for Fig. 7: E.g. c and f look dominant, which is only attributed to the different y-scale.

Typesetting:
- unify usage of % without leading space, i.e. 1% not 1 %
- l 309: delete “,” after scattering
- 418: “data, “ -> “data “
- 576: “surface, “ -> “surface “
- 615: thickness – correlated -> thickness-correlated
- Fig. 6: panel titles and caption: Rms looks unusual. The text uses RES and rms. I suggest to unify by writing RMS throughout the text or at least using RMS here.
- several very minor aspects are not conform with the typesetting instructions and will be dealt with during copyediting, e.g. usage of multiple braces for references, hyphenations, etc.

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AR by Thomas Jordan on behalf of the Authors (21 Apr 2017) Author's response Manuscript

Short summary

Using radio-echo sounding data from northern Greenland, we demonstrate that subglacial roughness exhibits self-affine (fractal) scaling behaviour. This enables us to assess topographic control upon the bed-echo waveform, and explain the spatial distribution of the degree of scattering (specular and diffuse reflections). Via comparison with a prediction for the basal thermal state (thawed and frozen regions of the bed) we discuss the consequences of our study for basal water discrimination.