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Evolution of the Lorenz Energy Cycle in the Intertropical Convergence Zone in the South American Sector of the Atlantic Ocean

Texto completo
Da Silva, Ligia A. [1, 2] ; Satyamurty, Prakki [2, 3]
Número total de Autores: 2
Afiliação do(s) autor(es):
[1] Univ Orleans, CNRS, Lab Phys & Chim Environm & Espace LPC2E, F-45071 Orleans - France
[2] Inst Nacl Pesquisas Espaciais, BR-12201 Sao Jose Dos Campos - Brazil
[3] Univ Estadual Amazonas, Manaus, Amazonas - Brazil
Número total de Afiliações: 3
Tipo de documento: Artigo Científico
Fonte: Journal of Climate; v. 26, n. 10, p. 3466-3481, MAY 2013.
Citações Web of Science: 0

The intertropical convergence zone (ITCZ) in the South American sector of the Atlantic Ocean is identified using outgoing longwave radiation (OLR) data in order to investigate the evolution of the Lorenz energy cycle in the region dominated by this large-scale feature. The NCEP reanalysis data are utilized to calculate the zonal and eddy components (denoted by Z and E, respectively) of kinetic energy K and available potential energy A(i.e., K-Z, K-E, A(Z), and A(E)) and their conversions, on a daily basis. A wavelet decomposition of the time series is performed to detect long-term cycles/trends in the Atlantic ITCZ region. This work also investigates trends in sea surface temperature (SST) and sea level pressure (SLP) in the ITCZ region and connections between the ITCZ and the Southern Oscillation index (SOI). A strong annual cycle in all the energy components with high peaks in austral summer is observed. Approximately 91% of the zonal component of energy is contained on decadal or longer time scales. The annual and semiannual variabilities are significant and the synoptic-scale variability is also present. The zonal component of kinetic energy K-Z presents a decreasing trend during the last 28 years, which means a weakening of trade winds in the region studied. The values of K-Z andA(E) are significantly higher during the period 1982/83, indicating that the intense El Nino-Southern Oscillation (ENSO) and/or the El Chichon eruption may have affected the circulation in the ITCZ region. The 28-yr mean energy conversion and generation terms are in general weaker than in the hemispheric calculations but the energy conversions proceed in the same sense as in the hemispheric situation. (AU)

Processo FAPESP: 11/13976-0 - Avaliações de impactos e vulnerabilidade às mudanças climáticas no Brasil e estratégias de opções de adaptação
Beneficiário:Lígia Alves da Silva
Linha de fomento: Bolsas no Brasil - Pós-Doutorado
Processo FAPESP: 08/58161-1 - Assessment of impacts and vulnerability to climate change in Brazil and strategies for adaptation option
Beneficiário:Jose Antonio Marengo Orsini
Linha de fomento: Auxílio à Pesquisa - Programa de Pesquisa sobre Mudanças Climáticas Globais - Temático