Expansion and Contraction of the Indo-Pacific Tropical Rain Belt over the Last Three Millennia.
The seasonal north-south migration of the intertropical convergence zone (ITCZ) defines the tropical rain belt (TRB), a region of enormous terrestrial and marine biodiversity and home to 40% of people on Earth. The TRB is dynamic and has been shown to shift south as a coherent system during periods of Northern Hemisphere cooling. However, recent studies of Indo-Pacific hydroclimate suggest that during the Little Ice Age (LIA; AD 1400-1850), the TRB in this region contracted rather than being displaced uniformly southward. This behaviour is not well understood, particularly during climatic fluctuations less pronounced than those of the LIA, the largest centennial-scale cool period of the last millennium. Here we show that the Indo-Pacific TRB expanded and contracted numerous times over multi-decadal to centennial scales during the last 3,000 yr. By integrating precisely-dated stalagmite records of tropical hydroclimate from southern China with a newly enhanced stalagmite time series from northern Australia, our study reveals a previously unidentified coherence between the austral and boreal summer monsoon. State-of-the-art climate model simulations of the last millennium suggest these are linked to changes in the structure of the regional manifestation of the atmosphere's meridional circulation.
Department of Geology, Cornell College, Mount Vernon, IA 52314, USA.
Rhawn F
RF
Denniston
Department of Physical Oceanography, Woods Hole Oceanographic Institution, Woods Hole, MA 02543, USA.
Caroline C
CC
Ummenhofer
Department of Geological and Atmospheric Sciences, Iowa State University, Ames, IA 50011 USA.
Alan D
AD
Wanamaker
Department of Geoscience, University of Nevada Las Vegas, Las Vegas, NV 89154, USA.
Matthew S
MS
Lachniet
IIHR-Hydroscience and Engineering, University of Iowa, Iowa City, IA 52240, USA.
Gabriele
G
Villarini
Department of Earth and Planetary Sciences, University of New Mexico, Albuquerque, NM 87131, USA.
Yemane
Y
Asmerom
Department of Earth and Planetary Sciences, University of New Mexico, Albuquerque, NM 87131, USA.
Victor J
VJ
Polyak
Department of Geology, Cornell College, Mount Vernon, IA 52314, USA.
Kristian J
KJ
Passaro
Australian Speleological Federation, Perth, Western Australia, Australia.
John
J
Cugley
Department of Parks and Wildlife, Broome, Western Australia, Australia.
David
D
Woods
School of Earth and Environment Sciences, University of Adelaide, Adelaide, South Australia.
William F
WF
Humphreys
Nat Commun. 2013;4:2908
24309539
Nature. 2007 Sep 27;449(7161):452-5
17898765
Proc Natl Acad Sci U S A. 2015 Apr 14;112(15):4576-81
25825740
Science. 2005 May 6;308(5723):854-7
15879216
Proc Natl Acad Sci U S A. 2011 May 24;108(21):8583-8
21555548
Science. 2001 Aug 17;293(5533):1304-8
11509727
Sci Rep. 2014 Oct 23;4:6739
25338702
Nature. 2014 Sep 4;513(7516):45-53
25186899
Sci Rep. 2014 Jun 04;4:5159
24894978
Science. 2008 Nov 7;322(5903):940-2
18988851
Nature. 2004 Dec 9;432(7018):740-3
15592409
Nature. 2012 Aug 16;488(7411):365-9
22895343
Science. 2000 Jul 14;289(5477):270-7
10894770
Science. 2001 Dec 14;294(5550):2345-8
11743199
Proc Natl Acad Sci U S A. 2010 Apr 13;107(15):6748-52
20351244