Universität zu Köln

Hou, Alicia, Bahr, Andre, Chiessi, Cristiano M., Jaeschke, Andrea ORCID: 0000-0003-2518-2739, Albuquerque, Ana Luiza S., Pross, Jorg, Koutsodendris, Andreas ORCID: 0000-0003-4236-7508 and Friedrich, Oliver ORCID: 0000-0002-6046-7513 (2022). Obliquity Influence on Low-Latitude Coastal Precipitation in Eastern Brazil During the Past similar to 850 kyr. Paleoceanogr. Paleoclimatology, 37 (2). WASHINGTON: AMER GEOPHYSICAL UNION. ISSN 2572-4525

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Abstract

Paleoclimate records from tropical South America typically show precession-paced variability in rainfall, caused by insolation-driven changes in the South American Monsoon System, however this mechanism may not be responsible for hydroclimate change outside of the core monsoon domain, such as in the coastal zone of tropical eastern Brazil. Our findings are based on a similar to 850 kyr-long multiproxy record from a marine sediment core collected from the eastern Brazilian margin that represents the longest continuous record of South American hydroclimate to date. Utilizing the ln (K/Al) chemical weathering proxy from the core, we determine that past hydroclimate change in the coastal zone was primarily modulated by obliquity forcing. We demonstrate that high obliquity is associated with an increase in the boreal summer interhemispheric insolation contrast which decreases the zonality of the southern trade winds and reduces moisture advection to the coastal zone. Based on the long-term coherence between the ln (K/Al) record and benthic delta C-13 records from the Atlantic during Marine Isotope Stages 16-13, we infer that an increase in the strength of the overturning circulation, caused by Northern Hemisphere high-latitude forcing, may have produced surface cooling in the western tropical South Atlantic which led to reduced moisture advection to the coastal zone. We suggest that this mechanism may have also caused the amplification in millennial-scale variability in the coastal hydroclimate system, which began after the decoupling of the coastal hydroclimate system from obliquity forcing.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Hou, Alicia UNSPECIFIED UNSPECIFIED UNSPECIFIED Bahr, Andre UNSPECIFIED UNSPECIFIED UNSPECIFIED Chiessi, Cristiano M. UNSPECIFIED UNSPECIFIED UNSPECIFIED Jaeschke, Andrea UNSPECIFIED orcid.org/0000-0003-2518-2739 UNSPECIFIED Albuquerque, Ana Luiza S. UNSPECIFIED UNSPECIFIED UNSPECIFIED Pross, Jorg UNSPECIFIED UNSPECIFIED UNSPECIFIED Koutsodendris, Andreas UNSPECIFIED orcid.org/0000-0003-4236-7508 UNSPECIFIED Friedrich, Oliver UNSPECIFIED orcid.org/0000-0002-6046-7513 UNSPECIFIED
URN:	urn:nbn:de:hbz:38-678957
DOI:	10.1029/2021PA004238
Journal or Publication Title:	Paleoceanogr. Paleoclimatology
Volume:	37
Number:	2
Date:	2022
Publisher:	AMER GEOPHYSICAL UNION
Place of Publication:	WASHINGTON
ISSN:	2572-4525
Language:	English
Faculty:	Unspecified
Divisions:	Unspecified
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language SOUTH-ATLANTIC; NORTHEASTERN BRAZIL; CHRONOLOGY AICC2012; ANTARCTIC ICE; CIRCULATION; PROXY; MONSOON; HISTORY; VARIABILITY; AMERICA Multiple languages Geosciences, Multidisciplinary; Oceanography; Paleontology Multiple languages
URI:	http://kups.ub.uni-koeln.de/id/eprint/67895