Centennial-scale solar forcing of the South American Monsoon System recorded in stalagmites.
The South American Monsoon System (SAMS) is generally considered to be highly sensitive to Northern Hemisphere (NH) temperature variations on multi-centennial timescales. The direct influence of solar forcing on moisture convergence in global monsoon systems on the other hand, while well explored in modeling studies, has hitherto not been documented in proxy data from the SAMS region. Hence little is known about the sensitivity of the SAMS to solar forcing over the past millennium and how it might compete or constructively interfere with NH temperature variations that occurred primarily in response to volcanic forcing. Here we present a new annually-resolved oxygen isotope record from a 1500-year long stalagmite recording past changes in precipitation in the hitherto unsampled core region of the SAMS. This record details how solar variability consistently modulated the strength of the SAMS on centennial time scales during the past 1500 years. Solar forcing, besides the previously recognized influence from NH temperature changes and associated Intertropical Convergence Zone (ITCZ) shifts, appears as a major driver affecting SAMS intensity at centennial time scales.
Instituto de Geociências, Universidade de São Paulo, São Paulo 05508-090, Brazil.
Valdir F
VF
Novello
Department of Atmospheric and Environmental Sciences, University at Albany, Albany, New York 12222, USA.
Mathias
M
Vuille
Instituto de Geociências, Universidade de São Paulo, São Paulo 05508-090, Brazil.
Francisco W
FW
Cruz
Instituto de Geociências, Universidade de São Paulo, São Paulo 05508-090, Brazil.|Departamento de Geoquímica, Universidade Federal Fluminense, Niterói, Rio de Janeiro 24220-900, Brazil.
Nicolás M
NM
Stríkis
Instituto de Geociências, Universidade de São Paulo, São Paulo 05508-090, Brazil.
Marcos Saito
MS
de Paula
Department of Earth Sciences, University of Minnesota, Minneapolis, Minnesota 55455, USA.
R Lawrence
RL
Edwards
Institute of Global Environmental Change, Xi'an Jiaotong University, Xi'an 710049, China.|Department of Earth Sciences, University of Minnesota, Minneapolis, Minnesota 55455, USA.
Hai
H
Cheng
Instituto de Geociências, Universidade de São Paulo, São Paulo 05508-090, Brazil.
Ivo
I
Karmann
Instituto de Astronomia, Geofísica e Ciências Atmosféricas, Universidade de São Paulo, São Paulo, Brazil.
Plínio F
PF
Jaqueto
Instituto de Astronomia, Geofísica e Ciências Atmosféricas, Universidade de São Paulo, São Paulo, Brazil.
Ricardo I F
RI
Trindade
Observatório Nacional, Rio de Janeiro 20921-400, Brazil.
Gelvam A
GA
Hartmann
Instituto de Geociências, Universidade de São Paulo, São Paulo 05508-090, Brazil.
Jean S
JS
Moquet