Mid- to Late Holocene Contraction of the Intertropical Convergence Zone Over Northeastern South America

Author(s):Show less -

Chiessi, C. M. ^[1] ; Mulitza, S. ^[2] ; Taniguchi, N. K. ^[3] ; Prange, M. ^[2] ; Campos, M. C. ^[1] ; Haeggi, C. ^{[2, 4]} ; Schefuss, E. ^[2] ; Pinho, T. M. L. ^[5] ; Frederichs, T. ^{[2, 6]} ; Portilho-Ramos, R. C. ^[2] ; Sousa, S. H. M. ^[3] ; Crivellari, S. ^[5] ; Cruz, F. W. ^[5]

Affiliation

^[1] Univ Sao Paulo, Sch Arts Sci & Humanities, Sao Paulo - Brazil

^[2] Univ Bremen, MARUM Ctr Marine Environm Sci, Bremen - Germany

^[3] Univ Sao Paulo, Inst Oceanog, Sao Paulo - Brazil

^[4] Univ Southern Calif, Dept Earth Sci, Los Angeles, CA 90007 - USA

^[5] Univ Sao Paulo, Inst Geosci, Sao Paulo - Brazil

^[6] Univ Bremen, Fac Geosci, Bremen - Germany

• Document type: Journal article
• Source: PALEOCEANOGRAPHY AND PALEOCLIMATOLOGY; v. 36, n. 4 APR 2021.
• Web of Science Citations: 0

Abstract

Modern precipitation over northeastern (NE) South America is strongly controlled by the seasonal meridional migration of the Intertropical Convergence Zone (ITCZ). Ample evidence from the Northern Hemisphere suggests a mid- to late Holocene southward migration of the ITCZ. Such a shift would be expected to increase precipitation over semi-arid northern NE Brazil (Southern Hemisphere). However, the most robust precipitation record from northern NE Brazil shows a drying trend throughout the Holocene. Here, we address this issue presenting a high-temporal resolution reconstruction of precipitation over northern NE Brazil based on data from a marine sediment core, together with analyses of mid- and late Holocene simulations performed with the fully coupled climate model FGOALS-s2. Both, our data and the climate model simulations show a decrease in precipitation over northern NE Brazil from the mid- to the late Holocene. The model outputs further indicate a latitudinal contraction of the seasonal migration range of the ITCZ that, together with an intensification of the regional Walker circulation, were responsible for the mid- to late Holocene changes in precipitation over NE South America. Our results reconcile apparently conflicting precipitation records and climate mechanisms used to explain changes in precipitation over NE South America. (AU)

• FAPESP's process: 18/15123-4 - Past perspectives on tipping elements of the climate system: the Amazon Rainforest and the Atlantic Meridional Overturning Circulation (PPTEAM)
• Grantee: Cristiano Mazur Chiessi
• Support Opportunities: Research Grants - Research Program on Global Climate Change - Young Investigators - Phase 2
• FAPESP's process: 19/10642-6 - Response of the upper water column at the origin of the Brazil Current to slowdown events of the Atlantic Meridional Ocean Circulation during the last 80 ka
• Grantee: Tainã Marcos Lima Pinho
• Support Opportunities: Scholarships in Brazil - Master
• FAPESP's process: 18/06790-7 - Variability of the Brazil Current and South American climate during the last glacial cycle: assessing sea-surface temperatures via Mg/Ca analyses and pulses of terrigenous sediments via X-ray fluorescence analyses
• Grantee: Marília de Carvalho Campos Garcia
• Support Opportunities: Scholarships abroad - Research Internship - Doctorate
• FAPESP's process: 19/24349-9 - Assessing the effects of past and future climate change on Amazonian biodiversity (CLAMBIO)
• Grantee: Cristiano Mazur Chiessi
• Support Opportunities: BIOTA-FAPESP Program - Regular Research Grants
• FAPESP's process: 13/10676-1 - Reconstitution of sea surface temperature and salinity in the equatorial Brazilian in Late Holocene: paleoclimate inferences
• Grantee: Nancy Kazumi Taniguchi
• Support Opportunities: Scholarships in Brazil - Master
• FAPESP's process: 16/10242-0 - Occurrence and impact of the mega-South Atlantic Convergence Zone over the eastern South America during the last glacial period: a paleoceanographic approach
• Grantee: Marília de Carvalho Campos Garcia
• Support Opportunities: Scholarships in Brazil - Doctorate