Análise Do Movimento Vertical Sob Duas Diferentes Configurações De Altos Níveis Da Troposfera

Abstract

The southern region of Brazil is potentially favorable the occurrence of extreme events, where these are due to different weather systems that operate in South America. Therefore various techniques have been exposed to improve the accuracy thereof, a characteristic what is present in many of them is the presence of troughs in the 500 hPa level. The present study aims to evaluate the vertical movement of two severe storm events that hit southern Brazil in the fall of 2013, one on 26 March and another on May 29, where both of them occurred from the same system type, but with different inclinations of the horizontal axis of the higher level trough of the atmosphere. For this were used data from the monthly compilation of significant cases of CPTEC / INPE for the choice of severe instability events. For the preparation of meteorological fields to be evaluated were reanalysis data used MERRA. This study showed that omega vertical upward movement was much more intense when related to the system associated with the negatively-trough (about 1.2 m s-1) while the upward movement associated with the positive-trough was around 0.5 m s-1.

South Atlantic explosive cyclones in 2014-2015: study employing NCEP2 and MERRA-2 reanalyses

“…Regardless of intensity, the negative horizontal inclination of the trough is observed in mid levels during the systems' development (Figures 5a,b,c,d,and e and 6a,b,c,d,and e). According to MacDonald (1976) and Cossetin et al (2016), the negative slope indicates extremely severe instability, which was a consequence of the significant increase in convective activity (not shown here).…”

Análise do Eixo Vertical de dois Ciclones Extratropicais na América do Sul

“…Esta inclinação horizontal segue diminuindo à medida que se aproximava do estágio de oclusão. Trabalhos no HN indicam maior probabilidade de instabilidade severa em casos de inclinação negativa devido a maior velocidade vertical ascendente (Glickman et al, 1977), mas tal comportamento não é tão facilmente observado em eventos na AS (Cossetin et al, 2016). Também é comum se observar a variação da inclinação ao longo do desenvolvimento do ciclone, conforme observado aqui.…”

Case Study of Upper Tropospheric Meteorological Systems on South America: Synoptic Analysis

“…Serão usados dados de diversas variáveis, para diferentes níveis verticais, para que se observe a estrutura vertical dos sistemas. As reanálises do MERRA são empregadas em vários trabalhos, como por exemplo em Quadro et al (2012), Wei et al (2013), Avila et al (2015) e Cossetin et al (2016), sendo, também, comparadas com outras reanálises (Kennedy et al, 2011;Hodges et al, 2011, entre outros) ou comparadas com dados de satélite (Posselt et al, 2012;Naud et al, 2014, entre outros). A nebulosidade associada aos sistemas é observada por meio de imagens de satélite obtidas da Divisão de Satélites e Sistemas Ambientais do Instituto Nacional de Pesquisas Espaciais (DSA/INPE).…”