Greenland annual accumulation along the EGIG line, 1959–2004, from ASIRAS
airborne radar and neutron-probe density measurements

Overly, Thomas B.; Hawley, Robert L.; Helm, Veit; Morris, Elizabeth M.; Chaudhary, Rohan N.

doi:https://doi.org/10.5194/tc-10-1679-2016

Articles | Volume 10, issue 4

https://doi.org/10.5194/tc-10-1679-2016

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

https://doi.org/10.5194/tc-10-1679-2016

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

Articles | Volume 10, issue 4

Research article

|

02 Aug 2016

Research article |

| 02 Aug 2016

Greenland annual accumulation along the EGIG line, 1959–2004, from ASIRAS airborne radar and neutron-probe density measurements

Thomas B. Overly, Robert L. Hawley, Veit Helm, Elizabeth M. Morris, and Rohan N. Chaudhary

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Final revised paper (published on 02 Aug 2016)
Preprint (discussion started on 14 Dec 2015)

Interactive discussion

Status: closed

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

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- Supplement

RC C2702: 'Comment on "Greenland annual accumulation along the EGIG line, 1959–2004, from ASIRAS airborne radar and detailed neutron-probe density measurements" by Overly et al.', Anonymous Referee #1, 08 Jan 2016
- AC C3280: 'Response to Anonymous Referee #1', Thomas Buckmaster Overly, 09 Mar 2016
SC C2928: 'Review for Overly et al.', Ginny Catania, 01 Feb 2016
- AC C3284: 'Author Response to G Catania', Thomas Buckmaster Overly, 09 Mar 2016
RC C2935: 'Review of Greenland annual accumulation along the EGIG line, 1959–2004, from ASIRAS airborne radar and detailed neutron-probe density measurements by T. B. Overly et al.', Lora Koenig, 02 Feb 2016
- AC C3286: 'Author Response to L. Koenig', Thomas Buckmaster Overly, 09 Mar 2016
RC C3009: 'Review of Greenland Annual Accumulation along the EGIG line, 1959-2004....', Anonymous Referee #3, 10 Feb 2016
- AC C3291: 'Author Response to Anonymous Referee #3', Thomas Buckmaster Overly, 09 Mar 2016

Peer-review completion

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

AR by Thomas Buckmaster Overly on behalf of the Authors (30 Apr 2016) Author's response Manuscript

ED: Referee Nomination & Report Request started (17 May 2016) by Marco Tedesco

RR by Anonymous Referee #3 (02 Jun 2016)

Suggestions for revision or reasons for rejection

Overall, the revised document is better organized and details about previous work and the processing of the results obtained much clearer. All of the concerns raised during the initial review were addressed.

The paper still relies on data previously published by Morris and Wingham (2011) and by de la Peña et al. (2010), but this is acceptable since the results serve to evaluate results from regional climate models and to assess Herron and Langley densification model. The conclusions could further emphasize on the differences between observations and the models, and when using Herron and Langley densities is advisable. As it is, the conclusions are still not significantly different from the conclusions in previous studies. However, the discussion regarding the ASIRAS derived accumulation using Herron and Langley and the comparison with models and the accumulation estimates using Neutron Probe densities is very good and an important assessment of our current capacity to measure and obtain estimates of annual accumulation.

I still have a problem following the signal that the retracker is picking at the deepest layers, especially in Figure A1. It is hard to see any signal below 25 m, and in some parts of the easternmost section, the tracker doesn’t seem to follow the signal correctly. It is hard to believe that the ASIRAS system can be used to estimate accumulation rates as far back as 1959 at the accuracy stated in the paper. Perhaps a more detailed explanation of the uncertainties at the deepest layers would help. The retracker does however a good job above 20 m, and the paper focuses more on accumulation rates starting in 1985.

I recommend the publication of this paper pending the details listed above, and a conclusions section listing the findings in the results beyond just accumulation rates but also the methodologies.

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RR by Lora Koenig (04 Jun 2016)

ED: Publish subject to minor revisions (Editor review) (11 Jun 2016) by Marco Tedesco

AR by Thomas Buckmaster Overly on behalf of the Authors (21 Jun 2016) Author's response Manuscript

ED: Publish as is (21 Jun 2016) by Marco Tedesco

AR by Thomas Buckmaster Overly on behalf of the Authors (28 Jun 2016)

Short summary

We demonstrate that snow accumulation rates across the Greenland Ice Sheet, determined from RADAR layers and modeled snow density profiles, are identical to ground-based measurements of snow accumulation. Three regional climate models underestimate snow accumulation compared to RADAR layer estimates. Using RADAR increases spatial coverage and improves accuracy of snow accumulation estimates. Incorporating our results into climate models may reduce uncertainty of sea-level rise estimates.