Thermal evolution of the western South Atlantic and the adjacent continent during Termination 1

Autor(es)

Chiessi, C. M. ^[1] ; Mulitza, S. ^[2] ; Mollenhauer, G. ^{[2, 3]} ; Silva, J. B. ^[4] ; Groeneveld, J. ^[2] ; Prange, M. ^[2]

Afiliação do(s) autor(es)

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

^[2] Univ Bremen, MARUM Ctr Marine Environm Sci, D-28359 Bremen - Germany

^[3] Alfred Wegener Inst Polar & Marine Res, Bremerhaven - Germany

^[4] Univ Sao Paulo, Inst Geosci, Sao Paulo - Brazil

• Tipo de documento: Artigo Científico
• Fonte: Climate of the Past; v. 11, n. 6, p. 915-929, 2015.
• Citações Web of Science: 11

Resumo

During Termination 1, millennial-scale weakening events of the Atlantic meridional overturning circulation (AMOC) supposedly produced major changes in sea surface temperatures (SSTs) of the western South Atlantic, and in mean air temperatures (MATs) over southeastern South America. It has been suggested, for instance, that the Brazil Current (BC) would strengthen (weaken) and the North Brazil Current (NBC) would weaken (strengthen) during slowdown (speed-up) events of the AMOC. This anti-phase pattern was claimed to be a necessary response to the decreased North Atlantic heat piracy during periods of weak AMOC. However, the thermal evolution of the western South Atlantic and the adjacent continent is so far largely unknown. Here we address this issue, presenting high-temporal-resolution SST and MAT records from the BC and southeastern South America, respectively. We identify a warming in the western South Atlantic during Heinrich Stadial 1 (HS1), which is followed first by a drop and then by increasing temperatures during the Bolling-Allerod, in phase with an existing SST record from the NBC. Additionally, a similar SST evolution is shown by a southernmost eastern South Atlantic record, suggesting a South Atlantic-wide pattern in SST evolution during most of Termination 1. Over southeastern South America, our MAT record shows a two-step increase during Termination 1, synchronous with atmospheric CO2 rise (i.e., during the second half of HS1 and during the Younger Dryas), and lagging abrupt SST changes by several thousand years. This delay corroborates the notion that the long duration of HS1 was fundamental in driving the Earth out of the last glacial. (AU)

• Processo FAPESP: 12/17517-3 - Resposta da porção oeste do Oceano Atlântico às mudanças na circulação meridional do Atlântico: variabilidade milenar a sazonal
• Beneficiário: Cristiano Mazur Chiessi
• Modalidade de apoio: Auxílio à Pesquisa - Programa de Pesquisa sobre Mudanças Climáticas Globais - Jovens Pesquisadores