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Insolation and Greenhouse Gas Forcing of the South American Monsoon System Across Three Glacial‐Interglacial Cycles
Author(s) -
Hou Alicia,
Bahr André,
Raddatz Jacek,
Voigt Silke,
Greule Markus,
Albuquerque Ana Luiza,
Chiessi Cristiano M.,
Friedrich Oliver
Publication year - 2020
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2020gl087948
Subject(s) - monsoon , climatology , interglacial , precipitation , forcing (mathematics) , glacial period , environmental science , ice core , marine isotope stage , greenhouse gas , climate change , geology , atmospheric sciences , physical geography , oceanography , geography , meteorology , geomorphology
Precipitation extremes with devastating socioeconomic consequences within the South American Monsoon System (SAMS) are expected to become more frequent in the near future. The complexity in SAMS behavior, however, poses severe challenges for reliable future projections. Thus, robust paleomonsoon records are needed to constrain the high spatiotemporal variability in the response of SAMS rainfall to different climatic drivers. This study uses Ti/Ca ratios from X‐ray fluorescence scanning of a sediment core retrieved off eastern Brazilian to trace precipitation changes over the past 322 Kyr. The results indicate that despite the spatiotemporal complexity of the SAMS, insolation forcing is the primary pacemaker of variations in the monsoonal system. Additional modulation by atmospheric p CO 2 suggests that SAMS intensity over eastern Brazil will be suppressed by rising CO 2 emissions in the future. Lastly, our record reveals an unprecedented strong and persistent wet period during Marine Isotope Stage 6 driven by anomalously strong trade winds.