Millennial-scale interhemispheric asymmetry of low-latitude precipitation: Speleothem evidence and possible high-latitude forcing

Xianfeng Wang, R. Lawrence Edwards, Augusto S. Auler, Hai Cheng, Emi Ito

Research output: Chapter in Book/Report/Conference proceedingChapter

10 Scopus citations

Abstract

During the last glacial period, global climate was characterized by numerous millennial-scale abrupt changes. Mechanisms of these events, however, are not yet resolved. Here, we use phasing information between climate records from different localities to distinguish between mechanisms. We establish a 90,000 year-long oxygen isotopic record of cave calcite, with our previously reported and newly obtained data from Caverna Botuverá, southern Brazil. The record was precisely dated with uranium-series methods. Using independent absolute-dated chronologies, we compare the southern Brazil record with contemporaneous oxygen isotopic records of cave calcite from eastern China and the record of speleothem growth periods from northeastern Brazil. Our record anti-correlates remarkably with the eastern China profile, while it correlates positively with the northeastern Brazil one, on both millennial and orbital scales. Thus, rainfall patterns are antiphased between southern Brazil and eastern China but in-phase between the two Brazilian regions. The in-phase Brazilian relationship argues against a Super El Niño-Southern Oscillation (Super-ENSO) mechanism as modern rainfall at these sites is out of phase during ENSO years. Rather, the relationship among the three records is likely related to displacement in the mean position of the intertropical convergence zone and associated asymmetry in Hadley circulation, which leads to an interhemispheric anti-phasing of rainfall between the southern and northern low latitudes. The abrupt climate events during the last glacial-interglacial cycle are probably triggered by meridional overturning circulation changes initiated in the high latitudes and then amplified through air-sea dynamics, resulting in the observed pattern of low-latitude precipitation.

Original languageEnglish (US)
Title of host publicationOcean Circulation
Subtitle of host publicationMechanisms and Impacts?Past and Future Changes of Meridional Overturning, 2007
EditorsAndreas Schmittner, John C. H. Chiang, Sidney R. Hemming
PublisherBlackwell Publishing Ltd
Pages279-294
Number of pages16
ISBN (Electronic)9781118666241
ISBN (Print)9780875904382
DOIs
StatePublished - 2007

Publication series

NameGeophysical Monograph Series
Volume173
ISSN (Print)0065-8448
ISSN (Electronic)2328-8779

Bibliographical note

Funding Information:
Hemming, Andreas Schmittner, John Chiang, and the anonymous reviewer, whose comments greatly helped in improving the original manuscript. We thank W.S. Broecker and G. Comer for their generous support of our work. Yongjin Wang and X. Kong are thanked for generously providing us the unpublished Shanbao Cave data. M. Solheid is acknowledged for helping with stable isotopic analyses. Cave sampling was performed with permission from IBAMA/CECAV. We thank the friendly collaboration of land owners and local people. This work was supported by NSF Grants ESH0214041, ESH0502535 and MRI0116395 (to R.L.E.), a Gary Comer Science & Education Foundation Grant CC8 (to R.L.E.), a CNPq grant 540064/01-7 of Brazil (to A.S.A.), and GSA research grants 7830-04 and 8163-05 (to X.W.).

Funding Information:
Many thanks to the editors, Sidney Hemming, Andreas Schmittner, John Chiang, and the anonymous reviewer, whose comments greatly helped in improving the original manuscript. We thank W.S. Broecker and G. Comer for their generous support of our work. Yongjin Wang and X. Kong are thanked for generously providing us the unpublished Shanbao Cave data. M. Solheid is acknowledged for helping with stable isotopic analyses. Cave sampling was performed with permission from IBAMA/CECAV. We thank the friendly collaboration of land owners and local people. This work was supported by NSF Grants ESH0214041, ESH0502535 and MRI0116395 (to R.L.E.), a Gary Comer Science & Education Foundation Grant CC8 (to R.L.E.), a CNPq grant 540064/01-7 of Brazil (to A.S.A.), and GSA research grants 7830-04 and 8163-05 (to X.W.).

Publisher Copyright:
© 2007 by the American Geophysical Union.

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