Estudo de Caso de Sistemas Meteorológicos em Altos Níveis Sobre a América do Sul: Análise Sinótica

Autores

  • André Becker Nunes Universidade Federal de Pelotas, Programa de Pós-Graduação em Meteorologia.

DOI:

https://doi.org/10.11137/2017_1_70_82

Palavras-chave:

vórtices ciclônicos de altos níveis, Alta da Bolívia, vento térmico, Palmén, Palmer

Resumo

O Vórtice ciclônico de altos níveis (VCAN) sobre o nordeste brasileiro (NeB) e a Alta da Bolívia (AB) são os típicos sistemas de pressão em altos níveis (250 hPa) da América do Sul, especialmente nas estações mais quentes. Somados a eles, também pode-se considerar o VCAN extratropical, de característica transiente e encontrado o ano todo. Neste trabalho, é apresentada uma análise sinótica, baseada na literatura especializada, de um caso observado em 01 de fevereiro de 2005 em que os três sistemas ocorreram simultaneamente. Algumas características encontradas na literatura foram observadas nos sistemas deste caso. O campo de temperatura mais associado ao sistema extratropical foi o de 500 hPa, e não o de 250 hPa. Os movimentos verticais mais relevantes foram encontrados somente no sistema extratropical: intensos movimentos ascendentes à sotavento do eixo do cavado em altos níveis. Não se encontrou um sistema em superfície especificamente associado ao VCAN do NeB, enquanto que se observou a baixa continental (ou Baixa do Chaco) associada à Alta da Bolívia e um intenso ciclone extratropical associado ao VCAN extratropical. Tal ciclone em superfície acarretou em vento sul e consequente resfriamento da camada, o que pôde ser observado pela amplitude do cavado em altos níveis, o que é raro para esta época do ano.

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2018-07-12

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