The influence of volcanic eruptions on the climate of tropical South America  during the last millennium in an isotope-enabled general  circulation model

Colose, Christopher M.; LeGrande, Allegra N.; Vuille, Mathias

doi:https://doi.org/10.5194/cp-12-961-2016

Articles | Volume 12, issue 4

https://doi.org/10.5194/cp-12-961-2016

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

https://doi.org/10.5194/cp-12-961-2016

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

Articles | Volume 12, issue 4

Research article

|

15 Apr 2016

Research article |

| 15 Apr 2016

The influence of volcanic eruptions on the climate of tropical South America during the last millennium in an isotope-enabled general circulation model

Christopher M. Colose, Allegra N. LeGrande, and Mathias Vuille

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Final revised paper (published on 15 Apr 2016)
Supplement to the final revised paper
Preprint (discussion started on 23 Jul 2015)
Supplement to the preprint

Interactive discussion

Status: closed

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

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RC C1443: 'Review of cp-2015-89 (Colose et al.)', Raphael Neukom, 21 Aug 2015
- AC C2175: 'Response to Dr. Raphael Neukom', Chris Colose, 02 Nov 2015
RC C1562: 'Review of the paper by C. M. Colose, A. N. LeGrande, and M. Vuille entitled “The influence of tropical volcanic eruptions on the climate of South America during the last millennium”', Anonymous Referee #2, 03 Sep 2015
- AC C2172: 'Response to Referee #2', Chris Colose, 02 Nov 2015
RC C1759: 'Blatant attempt to submit a rejected paper to another journal without addressing previous reviews', Anonymous Referee #3, 23 Sep 2015
- AC C2173: 'Response to Referee #3', Chris Colose, 02 Nov 2015
EC C1902: 'Editor comment', Valérie Masson-Delmotte, 05 Oct 2015
EC C1904: 'Editor comment', Valérie Masson-Delmotte, 05 Oct 2015

Peer-review completion

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

ED: Reconsider after major revisions (02 Nov 2015) by Valérie Masson-Delmotte

AR by Chris Colose on behalf of the Authors (15 Dec 2015) Author's response Manuscript

ED: Referee Nomination & Report Request started (19 Jan 2016) by Valérie Masson-Delmotte

RR by Raphael Neukom (02 Feb 2016)

Suggestions for revision or reasons for rejection

Review of revised version of Colose et al. 2016 (CPD)

This paper assesses the effects of large volcanic eruptions on temperature, precipitation and water isotopic composition in tropical South America. As such, it is a most welcome contribution to the literature. Knowledge gaps about the climatic response to volcanic events are still considerable, particularly in the Southern Hemisphere. Similarly, information about past millennium climate variability in South America (and many other regions of the globe) is still sparse, and quantification is challenging, particularly for hydroclimate. In tropical South America, most climate proxies are water isotope records and therefore understanding the climatic drivers behind the datasets is crucial. This paper is an important contribution for improving our understanding of these processes and I enjoyed reading it.

The authors have addressed all points that I have mentioned in my previous review. I therefore recommend that the article gets published in CP. I have three minor points that the authors may consider for the final version of the paper:

1. The signal remains quite weak in the observational period, due to the influence of internal variability and the relatively weak eruptions with still uncertain forcing. The authors have pointed out this in the text, with some additional paragraphs in the revised version. I think it is worth mentioning this caveat in the abstract (potentially accompanied by the argument that the LM model analysis is helpful in this regard thanks to the larger number of eruptions available and possibility to quantify the (internal-)noise component).

2. Are the correlation values in Figure 9 correct? From the Figure, I would rather expect significant values in both seasons for temperature and non-significant correlation for DJF-precip. Is it possible that the numbers got mixed up here or did I get something wrong?

3. I am a bit surprised by the weak signal in Fig. 12 bottom-right panel (isotopic response in JJA). This was not well visible in the figure in the first submission, so it did not call my attention. The purple square is hardly outside the range of values from the control simulation. In Fig. 10 the values seem to be quite large (mostly above 0.3 over the domain considered), so the value of ca. 0.15 in Fig. 12 appears to be too low. Is this because the northern part of the selected domain is affected by the negative values seen over the Atlantic? Would this make it worth moving the northern limit 1-2 degrees south to have a more consistent domain?
If not, I think it’s worth noting in the text that the signal is only marginally larger than internal variability for this specific season and variable.

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ED: Publish subject to minor revisions (review by Editor) (09 Feb 2016) by Valérie Masson-Delmotte

AR by Chris Colose on behalf of the Authors (20 Feb 2016) Author's response Manuscript

ED: Publish subject to technical corrections (24 Mar 2016) by Valérie Masson-Delmotte

AR by Chris Colose on behalf of the Authors (03 Apr 2016) Author's response Manuscript

Short summary

Volcanic forcing is the most important source of forced variability during the preindustrial component of the last millennium (~ 850-1850 CE) and is important during the last century.

Here, we focus on the climate impact over South America in a model-based study. Emphasis is given to temperature, precipitation, and oxygen isotope variability (allowing for potential contact made with paleoclimate-based observations)