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Equatorial Pacific forcing of western Amazonian precipitation during Heinrich Stadial 1

Abundant hydroclimatic evidence from western Amazonia and the adjacent Andes documents wet conditions during Heinrich Stadial 1 (HS1, 18–15 ka), a cold period in the high latitudes of the North Atlantic. This precipitation anomaly was attributed to a strengthening of the South American summer monsoo...

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Autores principales: Zhang, Yancheng, Zhang, Xu, Chiessi, Cristiano M., Mulitza, Stefan, Zhang, Xiao, Lohmann, Gerrit, Prange, Matthias, Behling, Hermann, Zabel, Matthias, Govin, Aline, Sawakuchi, André O., Cruz, Francisco W., Wefer, Gerold
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Nature Publishing Group 2016
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5078807/
https://www.ncbi.nlm.nih.gov/pubmed/27779213
http://dx.doi.org/10.1038/srep35866
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author Zhang, Yancheng
Zhang, Xu
Chiessi, Cristiano M.
Mulitza, Stefan
Zhang, Xiao
Lohmann, Gerrit
Prange, Matthias
Behling, Hermann
Zabel, Matthias
Govin, Aline
Sawakuchi, André O.
Cruz, Francisco W.
Wefer, Gerold
author_facet Zhang, Yancheng
Zhang, Xu
Chiessi, Cristiano M.
Mulitza, Stefan
Zhang, Xiao
Lohmann, Gerrit
Prange, Matthias
Behling, Hermann
Zabel, Matthias
Govin, Aline
Sawakuchi, André O.
Cruz, Francisco W.
Wefer, Gerold
author_sort Zhang, Yancheng
collection PubMed
description Abundant hydroclimatic evidence from western Amazonia and the adjacent Andes documents wet conditions during Heinrich Stadial 1 (HS1, 18–15 ka), a cold period in the high latitudes of the North Atlantic. This precipitation anomaly was attributed to a strengthening of the South American summer monsoon due to a change in the Atlantic interhemispheric sea surface temperature (SST) gradient. However, the physical viability of this mechanism has never been rigorously tested. We address this issue by combining a thorough compilation of tropical South American paleorecords and a set of atmosphere model sensitivity experiments. Our results show that the Atlantic SST variations alone, although leading to dry conditions in northern South America and wet conditions in northeastern Brazil, cannot produce increased precipitation over western Amazonia and the adjacent Andes during HS1. Instead, an eastern equatorial Pacific SST increase (i.e., 0.5–1.5 °C), in response to the slowdown of the Atlantic Meridional Overturning Circulation during HS1, is crucial to generate the wet conditions in these regions. The mechanism works via anomalous low sea level pressure over the eastern equatorial Pacific, which promotes a regional easterly low-level wind anomaly and moisture recycling from central Amazonia towards the Andes.
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spelling pubmed-50788072016-10-31 Equatorial Pacific forcing of western Amazonian precipitation during Heinrich Stadial 1 Zhang, Yancheng Zhang, Xu Chiessi, Cristiano M. Mulitza, Stefan Zhang, Xiao Lohmann, Gerrit Prange, Matthias Behling, Hermann Zabel, Matthias Govin, Aline Sawakuchi, André O. Cruz, Francisco W. Wefer, Gerold Sci Rep Article Abundant hydroclimatic evidence from western Amazonia and the adjacent Andes documents wet conditions during Heinrich Stadial 1 (HS1, 18–15 ka), a cold period in the high latitudes of the North Atlantic. This precipitation anomaly was attributed to a strengthening of the South American summer monsoon due to a change in the Atlantic interhemispheric sea surface temperature (SST) gradient. However, the physical viability of this mechanism has never been rigorously tested. We address this issue by combining a thorough compilation of tropical South American paleorecords and a set of atmosphere model sensitivity experiments. Our results show that the Atlantic SST variations alone, although leading to dry conditions in northern South America and wet conditions in northeastern Brazil, cannot produce increased precipitation over western Amazonia and the adjacent Andes during HS1. Instead, an eastern equatorial Pacific SST increase (i.e., 0.5–1.5 °C), in response to the slowdown of the Atlantic Meridional Overturning Circulation during HS1, is crucial to generate the wet conditions in these regions. The mechanism works via anomalous low sea level pressure over the eastern equatorial Pacific, which promotes a regional easterly low-level wind anomaly and moisture recycling from central Amazonia towards the Andes. Nature Publishing Group 2016-10-25 /pmc/articles/PMC5078807/ /pubmed/27779213 http://dx.doi.org/10.1038/srep35866 Text en Copyright © 2016, The Author(s) http://creativecommons.org/licenses/by/4.0/ This work is licensed under a Creative Commons Attribution 4.0 International License. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in the credit line; if the material is not included under the Creative Commons license, users will need to obtain permission from the license holder to reproduce the material. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/
spellingShingle Article
Zhang, Yancheng
Zhang, Xu
Chiessi, Cristiano M.
Mulitza, Stefan
Zhang, Xiao
Lohmann, Gerrit
Prange, Matthias
Behling, Hermann
Zabel, Matthias
Govin, Aline
Sawakuchi, André O.
Cruz, Francisco W.
Wefer, Gerold
Equatorial Pacific forcing of western Amazonian precipitation during Heinrich Stadial 1
title Equatorial Pacific forcing of western Amazonian precipitation during Heinrich Stadial 1
title_full Equatorial Pacific forcing of western Amazonian precipitation during Heinrich Stadial 1
title_fullStr Equatorial Pacific forcing of western Amazonian precipitation during Heinrich Stadial 1
title_full_unstemmed Equatorial Pacific forcing of western Amazonian precipitation during Heinrich Stadial 1
title_short Equatorial Pacific forcing of western Amazonian precipitation during Heinrich Stadial 1
title_sort equatorial pacific forcing of western amazonian precipitation during heinrich stadial 1
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5078807/
https://www.ncbi.nlm.nih.gov/pubmed/27779213
http://dx.doi.org/10.1038/srep35866
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