Ground surface temperature reconstruction for the last 500 years obtained from permafrost temperatures observed in the SHARE STELVIO Borehole, Italian Alps

Guglielmin, Mauro; Donatelli, Marco; Semplice, Matteo; Serra Capizzano, Stefano

doi:https://doi.org/10.5194/cp-14-709-2018

Articles | Volume 14, issue 6

https://doi.org/10.5194/cp-14-709-2018

© Author(s) 2018. This work is distributed under
the Creative Commons Attribution 3.0 License.

https://doi.org/10.5194/cp-14-709-2018

© Author(s) 2018. This work is distributed under
the Creative Commons Attribution 3.0 License.

Articles | Volume 14, issue 6

Research article

|

06 Jun 2018

Research article |

| 06 Jun 2018

Ground surface temperature reconstruction for the last 500 years obtained from permafrost temperatures observed in the SHARE STELVIO Borehole, Italian Alps

Mauro Guglielmin, Marco Donatelli, Matteo Semplice, and Stefano Serra Capizzano

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Final revised paper (published on 06 Jun 2018)
Preprint (discussion started on 02 Mar 2017)

Interactive discussion

Status: closed

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

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- Supplement

RC1: 'Review of the manuscript "cp-2017-23"', Anonymous Referee #1, 26 Apr 2017
RC2: 'Methodological shortcomings in manuscript', Volker Rath, 10 Jul 2017
AC1: 'Reply to Reviewers Comments', Mauro Guglielmin, 23 Jul 2017

Peer-review completion

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

ED: Reconsider after major revisions (25 Jul 2017) by Volker Rath

AR by Mauro Guglielmin on behalf of the Authors (15 Sep 2017) Author's response Manuscript

ED: Referee Nomination & Report Request started (13 Oct 2017) by Volker Rath

RR by Anonymous Referee #1 (04 Jan 2018)

Suggestions for revision or reasons for rejection

The manuscript has been revised and I appreciate the answers/amendments the authors provide. However, in my opinion, the concerns expressed the first previous review are only considered to a minimal extent, still leaving some important questions.

The remaining points are:
- Line 83: the PACE borehole revealed some ice fills karst, but this is still not discussed further. Is it justified to neglect this finding?
- In the figures, please state clearly what the different colors and line styles refer to.
- Figure 4,5 and Figure 8: the alpha value differs between the reconstructions using the synthetic and real data, why? As seen in Figure 4 and 5, a variation can lead to significantly different results.
- The caption of Fig. 9 is not clear – where do the temperature ranges come from? As seen from Fig. 14 they probably represent the uncertainty in the temperature measurements.
Consequently, it would be interesting to investigate the effect of this temperature uncertainty on the reconstructed GST history, not only showing it along with the temperature anomalies resulting from the reconstructed GST history.
- Fig. 9 is not cited in the manuscript text.
- Please justify your answer to the comment to line 167: „Numerical methods for the estimation of the regularization parameter, like GCV and L-curve, are not always reliable and in our case they provide an underestimation of the best value.“
- Lines 250 to 253: regarding the uncertainty in the reconstruction (which still needs to be determined in my opinion), is justified to give results in this precision (0.96 °C)?
- As mentioned the thermistor at the critical depth seemed to work properly, but this could have been investigated by varying the data used in the inversion (sensitivity study, uncertainty ranges, see comment above).
- 2D model: what would be the influence of the vertical extension of the model (background gradient…)
- I still consider a 3D model necessary in order to assess the 3D-effect on the temperature distribution, although the authors provide arguments that this would not yield further information.
Minor:
- Please check again, if “°C” is used for absolute temperatures and “K” for temperature differences (and the gradient, Table 1), this makes the distinction easier.
- Table 2: unit for thermal conductivity is not correct.

To summarize, the authors present interesting and valuable data which “deserves” a thorough investigation, which has not been done yet in my opinion. Therefore, I recommend another revision in order to do fully justice to the available data.

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ED: Reconsider after major revisions (04 Jan 2018) by Volker Rath

AR by Mauro Guglielmin on behalf of the Authors (12 Feb 2018) Author's response Manuscript

ED: Referee Nomination & Report Request started (26 Feb 2018) by Volker Rath

RR by Anonymous Referee #1 (01 May 2018)

ED: Publish subject to technical corrections (01 May 2018) by Volker Rath

AR by Mauro Guglielmin on behalf of the Authors (08 May 2018) Manuscript

Short summary

The reconstruction of ground surface temperature for the last 500 years, obtained at the deepest mountain permafrost borehole of the world (Stelvio Pass, 3000 m a.s.l., Italian Alps), is presented here. The main difference with respect to MAAT reconstructions obtained through other proxy data for all of Europe relates to post Little Ice Age (LIA) events. Indeed at this site a stronger cooling of ca 1 °C between 1940 and 1989 and even a more abrupt warming between 1990 and 2011 was detected.