Advecção de nebulosidade rasa sobre o sul do Brasil devido a atuação do anticiclone transiente na confluência Brasil-Malvinas
Autor(a) principal: | |
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Data de Publicação: | 2011 |
Tipo de documento: | Dissertação |
Idioma: | por |
Título da fonte: | Manancial - Repositório Digital da UFSM |
Texto Completo: | http://repositorio.ufsm.br/handle/1/10270 |
Resumo: | Advections of shallow cloudiness from ocean toward the continent are often observed after the cold fronts and extratropical cyclones on the Southern South America. Such a process has characteristic persistence of 1-2 days and it may last for periods longer than 3 consecutive days. This study identified 108 cases over the Southern Brazil between 2005 and 2010, which were characterized using NCEP/NCAR reanalysis. A seasonal climatology determined that the higher frequencies of cases were in autumn and summer, and the lower frequencies in spring and winter. The average wind directions that occurred over the Southern Brazil (Southwesterly, Southerly, Southeasterly and Easterly) were due to positioning of the center of the transient anticyclone over three major regions. Based on these results, it was obtained three synoptic patterns at lower and middle-higher levels. A seasonal distribution of those three patterns was also performed. In such mean situations, it was remarkable the displacement of cold air from the Region of Brazil-Malvinas Confluence (BMC) toward the Southern Brazil due to the circulation of the transient high. Along the way, the stable flow suffers low levels instability due to turbulent mixing processes, and heat and moisture fluxes when it passes from cold to warm waters on the BMC. As a consequence, a shallow convection layer develops downstream in the flow with wide support for the formation of stratiform and/or cumuliform cloud cover as it top. The synoptic patterns show the large scale air subsidence as an inhibiting mechanism for the development of a deep convective layer. Still, the cloud cover was enough to generate low intensity precipitation and/or drizzle over the Southern Brazil. The analysis of the precipitating cases showed that the phenomenon affected the coastal zone more frequently, and, sometimes, the inland areas. Mean vertical profiles of the 108 events, and peculiarly the precipitating ones, indicated the presence of a thick dry layer at the middle and upper levels, and a shallow moist layer at lower levels (1000-700 hPa). This study showed the importance of the Region BMC for the regional weather and climate patterns. It is shown that the circulation induced by transient anticyclone is essential for the transport of cold air from the cold to the warm waters in Confluence zone, generating and advecting shallow cloudiness and an unstable moist boundary layer over the South of Brazil. |
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Advecção de nebulosidade rasa sobre o sul do Brasil devido a atuação do anticiclone transiente na confluência Brasil-MalvinasAdvection of shallow cloudiness over southern Brazil due to the transient anticyclone flow over Brazil-Malvinas confluence regionAdvecção de nebulosidade rasaAnticiclone transienteConfluência Brasil-MalvinasAdvection of shallow cloudinessTransient anticycloneBrazil-Malvinas confluenceCNPQ::CIENCIAS EXATAS E DA TERRA::GEOCIENCIAS::METEOROLOGIAAdvections of shallow cloudiness from ocean toward the continent are often observed after the cold fronts and extratropical cyclones on the Southern South America. Such a process has characteristic persistence of 1-2 days and it may last for periods longer than 3 consecutive days. This study identified 108 cases over the Southern Brazil between 2005 and 2010, which were characterized using NCEP/NCAR reanalysis. A seasonal climatology determined that the higher frequencies of cases were in autumn and summer, and the lower frequencies in spring and winter. The average wind directions that occurred over the Southern Brazil (Southwesterly, Southerly, Southeasterly and Easterly) were due to positioning of the center of the transient anticyclone over three major regions. Based on these results, it was obtained three synoptic patterns at lower and middle-higher levels. A seasonal distribution of those three patterns was also performed. In such mean situations, it was remarkable the displacement of cold air from the Region of Brazil-Malvinas Confluence (BMC) toward the Southern Brazil due to the circulation of the transient high. Along the way, the stable flow suffers low levels instability due to turbulent mixing processes, and heat and moisture fluxes when it passes from cold to warm waters on the BMC. As a consequence, a shallow convection layer develops downstream in the flow with wide support for the formation of stratiform and/or cumuliform cloud cover as it top. The synoptic patterns show the large scale air subsidence as an inhibiting mechanism for the development of a deep convective layer. Still, the cloud cover was enough to generate low intensity precipitation and/or drizzle over the Southern Brazil. The analysis of the precipitating cases showed that the phenomenon affected the coastal zone more frequently, and, sometimes, the inland areas. Mean vertical profiles of the 108 events, and peculiarly the precipitating ones, indicated the presence of a thick dry layer at the middle and upper levels, and a shallow moist layer at lower levels (1000-700 hPa). This study showed the importance of the Region BMC for the regional weather and climate patterns. It is shown that the circulation induced by transient anticyclone is essential for the transport of cold air from the cold to the warm waters in Confluence zone, generating and advecting shallow cloudiness and an unstable moist boundary layer over the South of Brazil.Coordenação de Aperfeiçoamento de Pessoal de Nível SuperiorA advecção de nebulosidade rasa em direção ao continente após a passagem de frentes frias e ciclones extratropicais, pelo Sul da América do Sul, é um fenômeno frequentemente observado, e tem persistência característica de 1-2 dias, podendo durar por períodos superiores a 3 dias consecutivos. O presente estudo identificou sobre o Sul do Brasil 108 casos entre 2005 e 2010, os quais foram caracterizados utilizando reanálises do NCEP/NCAR. Uma climatologia sazonal definiu que as ocorrências foram mais frequentes no outono e no verão, e menores na primavera e no inverno. São apresentadas as direções médias do vento sobre o Sul do Brasil (Sudoeste, Sul, Sudeste e Leste), devido aos posicionamentos do centro do anticiclone sobre três regiões preferenciais. Com base nesses resultados, foram obtidos três padrões sinóticos, bem como suas distribuições sazonais. Evidenciou-se que o deslocamento da massa de ar frio a partir da Região de Confluência Brasil-Malvinas (CBM) em direção ao Sul do Brasil deve-se à ação do anticiclone transiente. Ao longo do percurso, ao passar sobre a CBM da região de águas frias para a região de águas aquecidas, o escoamento estável sofre instabilização em baixos níveis devido à processo de mistura turbulenta, fluxos de calor e umidade. Consequentemente, uma camada rasa de convecção desenvolve-se corrente abaixo do escoamento, com amplo suporte a formação de nebulosidade rasa dos tipos estratiforme e cumuliforme. Os padrões sinóticios mostram a subsidência em grande escala como mecanismo inibidor do desenvolvimento de uma camada convectiva profunda. Mesmo assim, tal cobertura de nuvens foi suficiente para gerar precipitação de fraca intensidade e/ou chuviscos sobre o Sul do Brasil. A análise dos eventos precipitantes mostrou que o fenômeno afetou com maior frequência a zona costeira, e, por vezes, o interior do continente. Perfis termodinâmicos médios dos 108 eventos, e especialmente dos casos precipitantes, indicaram a presença de uma espessa camada de ar seco em níveis médios e superiores, e uma camada rasa de ar úmido em baixos níveis (1000-700 hPa). Neste estudo evidenciou-se a importância da CBM para os padrões de tempo e clima regionais. Mostra-se que a circulação induzida pelo anticiclone transiente é fundamental para o transporte de ar frio da zona de águas frias para as águas quentes na Confluência, gerando e advectando nebulosidade rasa e uma camada limite úmida instável sobre o Sul do Brasil.Universidade Federal de Santa MariaBRMeteorologiaUFSMPrograma de Pós-Graduação em MeteorologiaAnabor, Vagnerhttp://lattes.cnpq.br/5770274675104746Dal Piva, Eversonhttp://lattes.cnpq.br/6060284080248352Pezzi, Luciano Ponzihttp://lattes.cnpq.br/9168878830863753Gan, Manoel Alonsohttp://lattes.cnpq.br/3214369697732376Kaufmann, Thomas2013-08-142013-08-142011-09-28info:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/masterThesisapplication/pdfapplication/pdfKAUFMANN, Thomas. Advection of shallow cloudiness over southern Brazil due to the transient anticyclone flow over Brazil-Malvinas confluence region. 2011. 114 f. Dissertação (Mestrado em Geociências) - Universidade Federal de Santa Maria, Santa Maria, 2011.http://repositorio.ufsm.br/handle/1/10270porinfo:eu-repo/semantics/openAccessreponame:Manancial - Repositório Digital da UFSMinstname:Universidade Federal de Santa Maria (UFSM)instacron:UFSM2023-05-31T17:23:28Zoai:repositorio.ufsm.br:1/10270Biblioteca Digital de Teses e Dissertaçõeshttps://repositorio.ufsm.br/ONGhttps://repositorio.ufsm.br/oai/requestatendimento.sib@ufsm.br||tedebc@gmail.comopendoar:2023-05-31T17:23:28Manancial - Repositório Digital da UFSM - Universidade Federal de Santa Maria (UFSM)false |
dc.title.none.fl_str_mv |
Advecção de nebulosidade rasa sobre o sul do Brasil devido a atuação do anticiclone transiente na confluência Brasil-Malvinas Advection of shallow cloudiness over southern Brazil due to the transient anticyclone flow over Brazil-Malvinas confluence region |
title |
Advecção de nebulosidade rasa sobre o sul do Brasil devido a atuação do anticiclone transiente na confluência Brasil-Malvinas |
spellingShingle |
Advecção de nebulosidade rasa sobre o sul do Brasil devido a atuação do anticiclone transiente na confluência Brasil-Malvinas Kaufmann, Thomas Advecção de nebulosidade rasa Anticiclone transiente Confluência Brasil-Malvinas Advection of shallow cloudiness Transient anticyclone Brazil-Malvinas confluence CNPQ::CIENCIAS EXATAS E DA TERRA::GEOCIENCIAS::METEOROLOGIA |
title_short |
Advecção de nebulosidade rasa sobre o sul do Brasil devido a atuação do anticiclone transiente na confluência Brasil-Malvinas |
title_full |
Advecção de nebulosidade rasa sobre o sul do Brasil devido a atuação do anticiclone transiente na confluência Brasil-Malvinas |
title_fullStr |
Advecção de nebulosidade rasa sobre o sul do Brasil devido a atuação do anticiclone transiente na confluência Brasil-Malvinas |
title_full_unstemmed |
Advecção de nebulosidade rasa sobre o sul do Brasil devido a atuação do anticiclone transiente na confluência Brasil-Malvinas |
title_sort |
Advecção de nebulosidade rasa sobre o sul do Brasil devido a atuação do anticiclone transiente na confluência Brasil-Malvinas |
author |
Kaufmann, Thomas |
author_facet |
Kaufmann, Thomas |
author_role |
author |
dc.contributor.none.fl_str_mv |
Anabor, Vagner http://lattes.cnpq.br/5770274675104746 Dal Piva, Everson http://lattes.cnpq.br/6060284080248352 Pezzi, Luciano Ponzi http://lattes.cnpq.br/9168878830863753 Gan, Manoel Alonso http://lattes.cnpq.br/3214369697732376 |
dc.contributor.author.fl_str_mv |
Kaufmann, Thomas |
dc.subject.por.fl_str_mv |
Advecção de nebulosidade rasa Anticiclone transiente Confluência Brasil-Malvinas Advection of shallow cloudiness Transient anticyclone Brazil-Malvinas confluence CNPQ::CIENCIAS EXATAS E DA TERRA::GEOCIENCIAS::METEOROLOGIA |
topic |
Advecção de nebulosidade rasa Anticiclone transiente Confluência Brasil-Malvinas Advection of shallow cloudiness Transient anticyclone Brazil-Malvinas confluence CNPQ::CIENCIAS EXATAS E DA TERRA::GEOCIENCIAS::METEOROLOGIA |
description |
Advections of shallow cloudiness from ocean toward the continent are often observed after the cold fronts and extratropical cyclones on the Southern South America. Such a process has characteristic persistence of 1-2 days and it may last for periods longer than 3 consecutive days. This study identified 108 cases over the Southern Brazil between 2005 and 2010, which were characterized using NCEP/NCAR reanalysis. A seasonal climatology determined that the higher frequencies of cases were in autumn and summer, and the lower frequencies in spring and winter. The average wind directions that occurred over the Southern Brazil (Southwesterly, Southerly, Southeasterly and Easterly) were due to positioning of the center of the transient anticyclone over three major regions. Based on these results, it was obtained three synoptic patterns at lower and middle-higher levels. A seasonal distribution of those three patterns was also performed. In such mean situations, it was remarkable the displacement of cold air from the Region of Brazil-Malvinas Confluence (BMC) toward the Southern Brazil due to the circulation of the transient high. Along the way, the stable flow suffers low levels instability due to turbulent mixing processes, and heat and moisture fluxes when it passes from cold to warm waters on the BMC. As a consequence, a shallow convection layer develops downstream in the flow with wide support for the formation of stratiform and/or cumuliform cloud cover as it top. The synoptic patterns show the large scale air subsidence as an inhibiting mechanism for the development of a deep convective layer. Still, the cloud cover was enough to generate low intensity precipitation and/or drizzle over the Southern Brazil. The analysis of the precipitating cases showed that the phenomenon affected the coastal zone more frequently, and, sometimes, the inland areas. Mean vertical profiles of the 108 events, and peculiarly the precipitating ones, indicated the presence of a thick dry layer at the middle and upper levels, and a shallow moist layer at lower levels (1000-700 hPa). This study showed the importance of the Region BMC for the regional weather and climate patterns. It is shown that the circulation induced by transient anticyclone is essential for the transport of cold air from the cold to the warm waters in Confluence zone, generating and advecting shallow cloudiness and an unstable moist boundary layer over the South of Brazil. |
publishDate |
2011 |
dc.date.none.fl_str_mv |
2011-09-28 2013-08-14 2013-08-14 |
dc.type.status.fl_str_mv |
info:eu-repo/semantics/publishedVersion |
dc.type.driver.fl_str_mv |
info:eu-repo/semantics/masterThesis |
format |
masterThesis |
status_str |
publishedVersion |
dc.identifier.uri.fl_str_mv |
KAUFMANN, Thomas. Advection of shallow cloudiness over southern Brazil due to the transient anticyclone flow over Brazil-Malvinas confluence region. 2011. 114 f. Dissertação (Mestrado em Geociências) - Universidade Federal de Santa Maria, Santa Maria, 2011. http://repositorio.ufsm.br/handle/1/10270 |
identifier_str_mv |
KAUFMANN, Thomas. Advection of shallow cloudiness over southern Brazil due to the transient anticyclone flow over Brazil-Malvinas confluence region. 2011. 114 f. Dissertação (Mestrado em Geociências) - Universidade Federal de Santa Maria, Santa Maria, 2011. |
url |
http://repositorio.ufsm.br/handle/1/10270 |
dc.language.iso.fl_str_mv |
por |
language |
por |
dc.rights.driver.fl_str_mv |
info:eu-repo/semantics/openAccess |
eu_rights_str_mv |
openAccess |
dc.format.none.fl_str_mv |
application/pdf application/pdf |
dc.publisher.none.fl_str_mv |
Universidade Federal de Santa Maria BR Meteorologia UFSM Programa de Pós-Graduação em Meteorologia |
publisher.none.fl_str_mv |
Universidade Federal de Santa Maria BR Meteorologia UFSM Programa de Pós-Graduação em Meteorologia |
dc.source.none.fl_str_mv |
reponame:Manancial - Repositório Digital da UFSM instname:Universidade Federal de Santa Maria (UFSM) instacron:UFSM |
instname_str |
Universidade Federal de Santa Maria (UFSM) |
instacron_str |
UFSM |
institution |
UFSM |
reponame_str |
Manancial - Repositório Digital da UFSM |
collection |
Manancial - Repositório Digital da UFSM |
repository.name.fl_str_mv |
Manancial - Repositório Digital da UFSM - Universidade Federal de Santa Maria (UFSM) |
repository.mail.fl_str_mv |
atendimento.sib@ufsm.br||tedebc@gmail.com |
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1805922074150043648 |