South American monsoon intensification during the last millennium driven by joint Pacific and Atlantic forcing
(2024) Science advances — Vol. 10, n° 38, p. 12 (2024)
Files
Lyuetal2024.pdf
Open Access - Adobe PDF
- 2.66 MB
Details
- Authors
Lyu, Zhiqiang 
Vuille, Mathias Orrison, Rebecca Cauhy, Julio
- Abstract
- 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.
- Affiliations
Citations
Lyu, Z., Vuille, M., Goosse, H., Orrison, R., Novello, V. F., Cruz, F. W., Stríkis, N. M., & Cauhy, J. (2024). South American monsoon intensification during the last millennium driven by joint Pacific and Atlantic forcing. Science advances, 10(38), 12. https://doi.org/10.1126/sciadv.ado9543 (Original work published 2024)