| Journal: | Revista brasileira de geofisica |
| Database: | PERIÓDICA |
| System number: | 000338459 |
| ISSN: | 0102-261X |
| Authors: | Santos, Jose Guilherme Martins dos1 Campos, Claudia Rejane Jacondino de2 Lima, Kellen Carla3 |
| Institutions: | 1Universidade de Sao Paulo, Instituto de Astronomia, Geofisica e Ciencias Atmosfericas, Sao Paulo. Brasil 2Universidade Federal de Pelotas, Departamento de Meteorologia, Pelotas, Rio Grande do Sul. Brasil 3Instituto Nacional de Pesquisas Espaciais, Centro de Previsao de Tempo e Estudos Climaticos, Sao Jose dos Campos, Sao Paulo. Brasil |
| Year: | 2008 |
| Season: | Oct-Dic |
| Volumen: | 26 |
| Number: | 4 |
| Pages: | 451-468 |
| Country: | Brasil |
| Language: | Portugués |
| Document type: | Artículo |
| Approach: | Analítico, descriptivo |
| English abstract | The Level Low Jet (LLJ) observed in the Porto Alegre metropolitan region, Rio Grande do Sul State, Brazil, was analyzed using 1989-2003 at 00:00 and 12:00 UTC upper-air observations. The LLJ classification criteria proposed by Bonner (1968) and modified by Whiteman et al. (1997) were applied to determine the LLJ occurrence. Afterwards was selected a LLJ event, that was one of the most intense observed in the summer (01/27/2002 at 12:00 UTC), during the study period. In this study were used as tools: atmospheric soundings, GOES-8 satellite images, and wind, temperature and specific humidity fields from GLOBAL, ETA and BRAMS models. Based on the numerical analysis was possible to verify that the three models overestimated the specific humidity and potential temperature values, at LLJ time occurrence. The wind speed was underestimated by the models. It was observed in the study region, at 12:00 UTC (LLJ detected hour in the Porto Alegre region), by three models, warm and wet air from north, generating conditions to Mesoscale Convective System (MCS) formation and intensification |
| Portuguese abstract | Para analisar a ocorrencia de Jatos de Baixos Nıveis (JBN) na regiao metropolitana de Porto Alegre, foram utilizados quinze anos de dados de radiossondagens coletadas nos horarios da 00:00 e das 12:00 UTC, no perıodo de 1989 a 2003. Para identificar as ocorencias dos JBN foram aplicados os criterios de classificacao propostos por Bonner (1968) e modificados por Whiteman et al. (1997). Em seguida, selecionou-se um evento de JBN (27/01/2002 as 12:00 UTC), que foi um dos mais intensos observados no verao durante o perıodo analisado. Para este estudo utilizaram-se como ferramentas: imagens do satelite geoestacionario GOES-8, radiossondagens e campos de vento, umidade especıfica e temperatura do arfornecidos pelos modelos GLOBAL, ETA e BRAMS |
| Disciplines: | Geociencias |
| Keyword: | Ciencias de la atmósfera, Corriente en chorro, Mesoescala, Vientos convectivos, Porto Alegre, Brasil |
| Keyword: | Earth sciences, Atmospheric sciences, Jet stream, Mesoscale, Convective winds, Porto Alegre, Brazil |
| Full text: | Texto completo (Ver PDF) |
