Centennial-scale precipitation anomalies in the southern Altiplano (18°&thinsp;S) suggest an extratropical driver for the South American summer  monsoon during the late Holocene

Jara, Ignacio A.; Maldonado, Antonio; González, Leticia; Hernández, Armand; Sáez, Alberto; Giralt, Santiago; Bao, Roberto; Valero-Garcés, Blas

doi:https://doi.org/10.5194/cp-15-1845-2019

Articles | Volume 15, issue 5

https://doi.org/10.5194/cp-15-1845-2019

© Author(s) 2019. This work is distributed under
the Creative Commons Attribution 4.0 License.

https://doi.org/10.5194/cp-15-1845-2019

© Author(s) 2019. This work is distributed under
the Creative Commons Attribution 4.0 License.

Articles | Volume 15, issue 5

Research article

|

16 Oct 2019

Research article |

| 16 Oct 2019

Centennial-scale precipitation anomalies in the southern Altiplano (18° S) suggest an extratropical driver for the South American summer monsoon during the late Holocene

Ignacio A. Jara, Antonio Maldonado, Leticia González, Armand Hernández, Alberto Sáez, Santiago Giralt, Roberto Bao, and Blas Valero-Garcés

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Final revised paper (published on 16 Oct 2019)
Supplement to the final revised paper
Preprint (discussion started on 15 Feb 2019)

Interactive discussion

Status: closed

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

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- Supplement

RC1: 'Review of Jara et al.', Anonymous Referee #1, 20 Mar 2019
- AC1: 'Responses to Referee #1', Ignacio Jara, 10 Jun 2019
RC2: 'Interactive comment on “Centennial-scale precipitation anomalies in the southern Altiplano (18◦ S) suggest an extra-tropical driver for the South American Summer Monsoon during the late Holocene”', Anonymous Referee #2, 22 May 2019
- AC2: 'Responses to Referee #2', Ignacio Jara, 10 Jun 2019

Peer-review completion

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

ED: Reconsider after major revisions (10 Jun 2019) by Hans Linderholm

AR by Ignacio Jara on behalf of the Authors (10 Jun 2019) Manuscript

ED: Referee Nomination & Report Request started (24 Jun 2019) by Hans Linderholm

RR by Anonymous Referee #3 (23 Jul 2019)

RR by Anonymous Referee #4 (04 Aug 2019)

Suggestions for revision or reasons for rejection

Review report cp-2019-13

I enjoyed reading the manuscript. It is a thoughtful and comprehensive study on a topic of great interest for Climate of the Past’s readership. The comments made by the reviewers in the interactive open discussion have been carefully incorporated, especially how different climate forcings are correlated to climatic teleconnections and its drivers for explaining precipitation anomalies in the Lake Chungara pollen record. I’m not an expert on this topic and so I only have suggestions for expanding the strength of modern pollen-environmental relationships to better interpret the fossil record.

How well the fossil pollen assemblages are represented by the surface vegetation types? It would be good to compute an unconstrained multivariate ordination analysis (e.g PCA) projecting the core samples into the ordination defined by modern pollen assemblages. In fact, it’d be even more relevant to carry out an ordination analysis with CCA or RDA constrained to climatic data (i.e. from WorldClim). By doing so, precipitation and/or temperature controls on fossil assemblages shifts could be assessed in a more nuanced way.

Is possible to comment on the idea of Equatorial Atlantic sea-surface temperature gradient variability to explain extra tropical source of moisture in Lake Chungara precipitation anomalies? Also, to what extent is possible to identify change in seasonality of precipitation anomalies in the Lake Chungara record?

Minor changes:
Line 156: “a few years later”
Line 179: It seems a bit contradictory to claim that the climate history of Lake Chungara is not well understood after such a great summary of paleolimnological and paleoclimatological studies carried out in the region over the last 20 years.
Line 198: please indicate which statistical software was used to carry out the CONISS analysis
Line 227: please change ordination by classification
Line 323: please change “periphylic” to “periphytic” (diatoms)
Line 356: replace “in the core” by “in the central”

Referee Report: PDF

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ED: Publish subject to minor revisions (review by editor) (04 Aug 2019) by Hans Linderholm

AR by Ignacio Jara on behalf of the Authors (13 Aug 2019)

ED: Publish as is (13 Sep 2019) by Hans Linderholm

AR by Ignacio Jara on behalf of the Authors (18 Sep 2019) Manuscript

Short summary

The South American summer monsoon (SASM) is the most important climate system of South America. However, little is known about its long-term variability. Here we present a new SASM reconstruction from Lago Chungará in the southern Altiplano (18°S). We show important changes in SASM precipitation at timescales of centuries. Our results suggest that SASM variability was controlled not only by tropical climates but was also influenced by precipitation outside the tropics.