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Title: South American monsoon intensification during the last millennium driven by joint Pacific and Atlantic forcing
The South American summer monsoon (SASM) profoundly influences tropical South America’s climate, yet understanding its low-frequency variability has been challenging. Climate models and oxygen isotope data have been used to examine the SASM variability over the last millennium (LM) but have, at times, provided conflicting findings, especially regarding its mean-state change from the Medieval Climate Anomaly to the Little Ice Age. Here, we use a paleoclimate data assimilation (DA) method, combining model results and δ18O observations, to produce a δ18O-enabled, dynamically coherent, and spatiotemporally complete austral summer hydroclimate reconstruction over the LM for tropical South America at 5-year resolution. This reconstruction aligns with independent hydroclimate and δ18O records withheld from the DA, revealing a centennial-scale SASM intensification during the MCA-LIA transition period, associated with the southward shift of the Atlantic Intertropical Convergence Zone and the strengthening Pacific Walker circulation (PWC). This highlights the necessity of accurately representing the PWC in climate models to predict future SASM changes.  more » « less
Award ID(s):
1743738 2402113
PAR ID:
10555915
Author(s) / Creator(s):
; ; ; ; ; ; ;
Publisher / Repository:
Science Advances
Date Published:
Journal Name:
Science Advances
Volume:
10
Issue:
38
ISSN:
2375-2548
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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