Normal Mode Perspective on the 2016 QBO Disruption: Evidence for a Basic State Regime Transition

Autor(es)

Raphaldini, Breno ^[1] ; Wakate Teruya, Andre Seiji ^[1] ; Silva Dias, Pedro Leite ^[1] ; Chavez Mayta, Victor Raul ^[1] ; Takara, Victor Junji ^[2]

Afiliação do(s) autor(es)

^[1] Univ Sao Paulo, Inst Astron Geofis & Ciencias Atmosfer, Dept Ciencias Atmosfer, Sao Paulo - Brazil

^[2] Univ Sao Paulo, Inst Matemat & Estat, Sao Paulo - Brazil

• Tipo de documento: Artigo Científico
• Fonte: Geophysical Research Letters; v. 47, n. 14 JUL 28 2020.
• Citações Web of Science: 0

Resumo

A normal mode decomposition of the dynamical structure of the quasi-biennial oscillation (QBO) is presented in this article. It was found that the QBO is predominantly described by Rossby modes as well as westward inertio-gravity modes with a low meridional mode index. We show that the 2016 QBO disruption was accompanied by an extreme amplitude event of an asymmetric zonal Rossby mode (with meridional index 4) consisting of the largest amplitude in 40 years. This component of the zonal flow favors the convergence of eastward momentum in the equatorial region, controlling the perturbations to the QBO. The zonal winds associated with this mode are extremely intermittent with heavy tail distributions. Our statistical analysis indicates a regime transition in this zonal mode in the recent decades, favoring stronger perturbations to the QBO. (AU)

• Processo FAPESP: 15/50686-1 - Paleo-vínculos na evolução das monções e dinâmica
• Beneficiário: Pedro Leite da Silva Dias
• Modalidade de apoio: Auxílio à Pesquisa - Temático
• Processo FAPESP: 17/23417-5 - Variabilidade paleoclimática da Zona de Convergência do Atlântico Sul e processos no Oceano Atlântico e Pacífico: Último Glacial, Holoceno Médio e Último Milênio
• Beneficiário: Breno Raphaldini Ferreira da Silva
• Modalidade de apoio: Bolsas no Brasil - Pós-Doutorado