| Texto completo | |
| Autor(es): Mostrar menos - |
Vasconcelos, Lucas C.
;
Cruz, Francisco W.
;
Bernal, Juan Pablo
;
Campos, Marilia C.
;
Piacsek, Patricia
;
Campos, Jose L.
;
Zhang, Haiwei
;
Strikis, Nicolas
;
Vuille, Mathias
;
Utida, Giselle
;
Millo, Christian
;
Edward, R. Lawrence
;
Cheng, Hai
Número total de Autores: 13
|
| Tipo de documento: | Artigo Científico |
| Fonte: | GLOBAL AND PLANETARY CHANGE; v. 255, p. 15-pg., 2025-10-19. |
| Resumo | |
The long-term variations in rainfall amount over southern Brazil are thought to be mainly driven by insolation forcing on the South American Monsoon System (SAMS). However, the bimodal rainfall regime over the region limits the interpretations from pioneering studies using 518O in stalagmites. Here, we display high-resolution trace elements data from the Botuvera Cave (27 degrees S) as a proxy for paleo-precipitation amount covering the Last Glacial Period (LGP). Our record highlights an in-phase variation between Mg/Ca, Sr/Ca, and 518O for the first two insolation cycles, suggesting increased precipitation due to enhanced monsoon activity during high austral summer insolation. From 60 to 10 ky BP, our geochemistry data do not follow insolation equally well, suggesting that Atlantic Meridional Overturning Circulation (AMOC) might interplay with precession as drivers for long-term paleo-precipitation changes in southern Brazil. We compare the speleothem record to marine SST records to identify feedback mechanisms between the atmospheric circulation and South Atlantic SST characterized by a stronger SAMS and colder SSTs relationship in adjacent South Atlantic. Two modes of precipitation variability are proposed: 1) from 113.5 to 40 ky BP, an in-phase precipitation variability between the areas affected by the South Atlantic Convergence Zone (SACZ) and southeast South America (SESA); and 2) from 40 to 10 ky BP, a precipitation dipole is identified between SACZ and SESA, respectively. For the millennial timescale, our Sr/Ca and Mg/Ca data indicate that there exists a relationship between higher precipitation and enhanced SAMS during some Heinrich Stadial (HSs) and Glacial Interstadial (GI) events. We argue that the monsoon circulation and its related cloudiness band play an important role in affecting SST changes over the South Atlantic at distinct timescales. (AU) | |
| Processo FAPESP: | 22/08359-7 - Padrões inter-hemisférico de precipitação monçônica sob diferentes condições de temperatura nos últimos 140 KA e no Antropoceno |
| Beneficiário: | Francisco William da Cruz Junior |
| Modalidade de apoio: | Auxílio à Pesquisa - Programa de Pesquisa sobre Mudanças Climáticas Globais - Regular |
| Processo FAPESP: | 23/05764-0 - O Atlântico Sul em um planeta 2°C mais quente |
| Beneficiário: | Marília de Carvalho Campos Garcia |
| Modalidade de apoio: | Bolsas no Brasil - Projeto Geração |
| Processo FAPESP: | 22/06452-0 - O Atlântico Sul em um planeta 2°C mais quente |
| Beneficiário: | Marília de Carvalho Campos Garcia |
| Modalidade de apoio: | Auxílio à Pesquisa - Projeto Geração |