Pacific Interannual and Multidecadal Variability Recorded in δ¹⁸O of South American Summer Monsoon Precipitation

Autor(es)

Orrison, R. ; Vuille, M. ; Rodrigues, J. C. ; Strikis, N. M. ; Cruz, F. ; Rodriguez-Caton, M. ; Andreu-Hayles, L.

• Tipo de documento: Artigo Científico
• Fonte: JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES; v. 129, n. 17, p. 19-pg., 2024-09-16.

Resumo

The South American summer monsoon (SASM) generates important hydroclimatic impacts in (sub-)tropical South America and isotopic tracers recorded in paleoclimatic archives allow for assessing its long-term response to Pacific variability prior to modern observations. Stable oxygen isotopes in precipitation integrate hydroclimatic changes during the SASM mature phase from December to February (DJF) in response to the Interdecadal Pacific Oscillation (IPO) and El Ni & ntilde;o-Southern Oscillation (ENSO), respectively. Here, results from the isotope-enabled Community Atmosphere Model v.5 are compared with highly resolved and precisely dated isotopic records from speleothems, tree rings, lake and ice cores during the industrial era (1880-2000 CE) and validated against observations from the International Atomic Energy Agency (IAEA) network. Pacific sea surface temperatures (SSTs) are coupled to the isotopic composition of SASM precipitation through perturbations in the Walker circulation associated with low- (IPO) and high-frequency (ENSO) variability, impacting convective activity over tropical South America and the tropical Atlantic. Changes in convection over this monsoon entrance region ultimately control the downstream oxygen isotopic composition of precipitation recorded in paleoclimate archives. Overall, model results, paleoclimate records and IAEA data agree on the isotopic response to Pacific SST forcing. These results highlight the potential for long isotopic paleoclimate records to reconstruct Pacific climate variability on both high- and low-frequency timescales. Furthermore, the isolation of the IPO signal in a diverse set of isotopic archives invites the reinterpretation of other paleoclimate proxies for identifying this historically overlooked forcing. (AU)

• Processo FAPESP: 17/50085-3 - PIRE: educação e pesquisa em clima das Américas usando os exemplos de anéis de árvores e espeleotemas (PIRE-CREATE)
• Beneficiário: Francisco William da Cruz Junior
• Modalidade de apoio: Auxílio à Pesquisa - Temático
• Processo FAPESP: 19/02791-1 - Estudo sobre a variabilidade de eventos extremos de chuva com base em análises geoquímicas de alta resolução (d18O e d13C e elementos traços) em espeleotemas
• Beneficiário: Julio Cauhy Rodrigues
• Modalidade de apoio: Bolsas no Brasil - Mestrado
• 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