An Analysis of the Energetics of Tropical and Extra-Tropical Regions for Warm ENSO Composite Episodes

Abstract

This study focuses on the quantification and evaluation of the effects of ENSO (El Niño Southern Oscillation) warm phases, using a composite of five intense El Niño episodes between 1979 -2011 on the Energetic Lorenz Cycle for four distinct regions around the globe: 80°S -5°N (region 1), 50°S -5°N (region 2), 30°S -5°N (region 3), and 30°S -30°N(region 4), using Data from NCEP reanalysis-II. Briefly, the results showed that zonal terms of potential energy and kinetic energy were intensified, except for region 1, where zonal kinetic energy weakened. Through the analysis of the period in which higher energy production is observed, a strong communication between the available zonal potential and the zonal kinetic energy reservoirs can be identified. This communication weakened the modes linked to eddies of potential energy and kinetic energy, as well as in the other two baroclinic conversions terms. Furthermore, the results indicate that for all the regions, the system itself works to regain its stable condition. Keywords: atmospheric energetics, Lorenz Cycle, ENSO, El Niño. Uma Análise da Energética de Regiões Tropicais e Extra-Tropicais para um Composto de Episódios Quentes de ENOS ResumoEste estudo foca na quantificação e avaliação dos efeitos da fase quente de eventos ENOS (El Niño -Oscilação Sul), utilizando um composto de cinco intensos episódios de El Niño entre 1979 -2011, no Ciclo Energético Lorenz por quatro regiões distintas ao redor do globo: 80°S -5°N (domínio 1), 50°S -5°N (domínio 2), 30°S -5°N (domínio 3), e 30°S -30°N (domínio 4), utilizando os Dados do NCEP -Reanálise 2. Resumidamente, os resultados mostraram que termos zonais de energia potencial e energia cinética foram intensificadas, com exceção da região 1, onde a energia cinética zonal enfraqueceu. Através da análise do período em que é observada maior produção de energia, observa-se uma forte comunicação entre os reservatórios de energia potencial disponível zonal e energia cinética zonal. Esta comunicação enfraqueceu o modo associado à perturbação de energia potencial e cinética, bem como nos outros dois termos conversões baroclínicas. Além disso, os resultados indicam que, para todas as regiões, o sistema funciona para recuperar o seu estado estável. Palavras-chave: energética atmosférica, Ciclo de Lorenz, ENSO, El Niño.

Behavior of the ITCZ second band near the Peruvian coast during the 2017 coastal El Niño

“…Other peaks of KE were present in the first half of February and March, but with values close to half of those obtained in January. This decrease in KE can be related to the presence of a CEN event, which was also found by Veiga et al (2013) and Sátyro and Veiga (2017) in warm ENSO episodes, due to the decrease in the transfer of KE from the environment to the area of the second band, as the warming generated by CEN in the entire eastern Pacific region near Peru did not allow for significant thermal gradients that generate energy transfer. The peaks of KE in the first half of February and March are related to maximums of precipitation in the ITCZ's second band (Figure 5), this can be explained by the increased of the convection during this period.…”