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@PhDThesis{Ribeiro:2018:LiInSu,
               author = "Ribeiro, Bruno Zanetti",
                title = "Linhas de instabilidade no Sul do Brasil",
               school = "Instituto Nacional de Pesquisas Espaciais (INPE)",
                 year = "2018",
              address = "S{\~a}o Jos{\'e} dos Campos",
                month = "2018-05-30",
             keywords = "linhas de instabilidade, Sul do Brasil, climatologia 
                         sin{\'o}tica, tempo severo, simula{\c{c}}{\~a}o num{\'e}rica, 
                         squall lines, Southern Brazil, synoptic climatology, severe 
                         weather, numerical simulation.",
             abstract = "Este estudo mostra uma climatologia de Linhas de Instabilidade 
                         (LIs) no Sul do Brasil. As LIs s{\~a}o identificadas por imagens 
                         de radar, e s{\~a}o classificadas em severas ou n{\~a}o severas 
                         com base em relatos de destrui{\c{c}}{\~a}o causada pelo vento 
                         ou medidas de rajada de vento de pelo menos 80 km h\−1 por 
                         esta{\c{c}}{\~o}es de superf{\'{\i}}cie. Com base nos campos 
                         sin{\'o}ticos em 500 hPa, as LIs s{\~a}o agrupadas em tr{\^e}s 
                         tipos sin{\'o}ticos. Dados da rean{\'a}lise CFSR s{\~a}o 
                         utilizados para produzir compostos do ambiente sin{\'o}tico em 
                         que ocorrem LIs severas e n{\~a}o severas de cada tipo 
                         sin{\'o}tico, al{\'e}m de gerar distribui{\c{c}}{\~o}es 
                         estat{\'{\i}}sticas de par{\^a}metros de tempo severo. Dois 
                         casos de LI severas s{\~a}o simulados com o modelo WRF com 
                         convec{\c{c}}{\~a}o permitida e resolu{\c{c}}{\~a}o de 3 km. 
                         As LIs s{\~a}o mais comuns na primavera, quando tamb{\'e}m 
                         ocorrem os maiores percentuais de LIs severas. A maior parte das 
                         LIs ocorre durante a madrugada e a manh{\~a}, mas o maior 
                         percentual de LI severas {\'e} {\`a} tarde. LIs com deslocamento 
                         mais r{\'a}pido t{\^e}m maior chance de ser severas, 
                         principalmente se o deslocamento for maior que 50 km h\−1. 
                         Os compostos dos campos sin{\'o}ticos mostram que h{\'a} 
                         advec{\c{c}}{\~a}o quente e converg{\^e}ncia do fluxo de 
                         umidade em baixos n{\'{\i}}veis associadas {\`a}s LIs no Sul do 
                         Brasil. A instabilidade termodin{\^a}mica e o DCAPE na 
                         regi{\~a}o s{\~a}o maiores em casos de LI severas de todos os 
                         tipos sin{\'o}ticos. A configura{\c{c}}{\~a}o sin{\'o}tica 
                         mais recorrente quando ocorrem LIs tem como 
                         caracter{\'{\i}}stica um cavado na m{\'e}dia troposfera 
                         corrente acima do Brasil, e os sistemas sin{\'o}ticos s{\~a}o 
                         mais intensos em casos severos desse tipo. Quando o cavado em 
                         m{\'e}dios n{\'{\i}}veis se encontra a oeste dos Andes, os 
                         ambientes associados a LIs severas t{\^e}m como principal 
                         diferencial a maior instabilidade termodin{\^a}mica e maior 
                         DCAPE. LIs que ocorrem em ambientes com predom{\'{\i}}nio de 
                         escoamento zonal na m{\'e}dia troposfera t{\^e}m maior 
                         tend{\^e}ncia de ser severas quanto maior for o cisalhamento do 
                         vento entre 1000 e 500 hPa. Os par{\^a}metros de tempo severo com 
                         maior poder discriminat{\'o}rio da severidade das LIs s{\~a}o o 
                         CAPE e o DCAPE, e o cisalhamento para casos com escoamento zonal. 
                         A simula{\c{c}}{\~a}o num{\'e}rica da LI de 19/10/2014 mostrou 
                         que a vorticidade horizontal no ambiente permitiu a 
                         organiza{\c{c}}{\~a}o da linha convectiva. A 
                         forma{\c{c}}{\~a}o de um v{\'o}rtice meso- e a descida do jato 
                         de retaguarda associada a um eco de arco foram as principais 
                         causas das rajadas de vento severas nesse caso. A LI de 
                         20/12/2014, por outro lado, n{\~a}o esteve associada a um intenso 
                         jato de retaguarda, mas a intensa piscina fria causada pela 
                         precipita{\c{c}}{\~a}o da LI e a forma{\c{c}}{\~a}o de 
                         v{\'o}rtices meso- ao longo da linha convectiva causaram as 
                         rajadas de vento severas. A estrutura de mesoalta e mesobaixas 
                         associada {\`a}s LIs foram muito similares aos modelos 
                         conceituais de LIs assim{\'e}tricas. As distribui{\c{c}}{\~o}es 
                         de flutuabilidade, perturba{\c{c}}{\~a}o de press{\~a}o e 
                         vorticidade horizontal tamb{\'e}m se assemelham aos modelos 
                         conceituais, e confirmam que as LIs no SB t{\^e}m diversas 
                         caracter{\'{\i}}sticas de mesoescala similares {\`a}s que 
                         ocorrem em outros lugares do mundo. ABSTRACT: This study presents 
                         a climatology of squall lines in Southern Brazil. The squall lines 
                         are identified by radar imagery, and classified in severe or 
                         non-severe based on wind-related damage reports or wind gusts of 
                         at least 80 km h\−1 measured by surface stations. Based on 
                         the 500-hPa synoptic fields, the squall lines are grouped in three 
                         synoptic types. CFS Reanalysis data are used to build composites 
                         of the environments where severe and non-severe squall lines under 
                         each synoptic configuration type occur, and generate statistical 
                         distributions of severe thunderstorm parameters. Two significantly 
                         severe squall lines were simulated using the WRF model with 
                         convection-allowing configuration and 3 km of horizontal 
                         resolution. Squall lines are more common during Spring, when the 
                         highest percentages of severe squall lines are also observed. The 
                         majority of the squall lines occur during late night and morning, 
                         but the percentages of severe squall lines are higher in the 
                         afternoon. Squall lines that move faster have higher chance of 
                         being severe, mainly if the squall-line speed exceeds 50 km 
                         h\−1. The synoptic composites show low-level warm advection 
                         and moisture flux convergence are present when squall lines occur 
                         in Southern Brazil. The thermodynamic instability and DCAPE in the 
                         region are higher in severe squall line cases of all synoptic 
                         types. The most recurrent synoptic configuration when squall lines 
                         are observed is characterized by a midlevel trough upstream of 
                         Southern Brazil, and the synoptic systems near the region are more 
                         intense in severe cases of this type. When the midlevel trough is 
                         located west of the Andes, the main differences in severe and 
                         non-severe squall line environments are the thermodynamic 
                         instability and DCAPE. Squall lines occurring under strong zonal 
                         midlevel flow have higher chances of being severe as stronger is 
                         the 1000\−500- hPa wind shear. The severe thunderstorm 
                         parameters with higher discriminatory capacity of the squall lines 
                         severity are CAPE and DCAPE, and the wind shear in cases of zonal 
                         midlevel flow. The 19 October 2014 squall line numerical 
                         simulation showed that horizontal vorticity in the pre-squall line 
                         environment organized the convective line. The formation of a 
                         meso--scale vortex and rear inflow jet descent associated with a 
                         bow echo were the main causes of severe wind gusts in this case. 
                         The 20 December 2014 squall line, on the other hand, was not 
                         associated with an intense rear inflow jet, but the strong cold 
                         pool caused by the squall line precipitation evaporative cooling 
                         and the formation of several meso- -scale vortices along the 
                         convective line were responsible for the severe wind gusts. The 
                         mesohigh and mesolow structures were very similar to conceptual 
                         models of asymmetric squall lines. The distributions of buoyancy, 
                         pressure perturbation and horizontal vorticity are also comparable 
                         to most conceptual models, and confirm that squall lines in 
                         Southern Brazil are similar to squall lines in other parts of the 
                         world.",
            committee = "Herdies, Dirceu Luis (presidente) and Seluchi, Marcelo Enrique 
                         (orientador) and Satyamurty, Prakki and Silva Dias, Maria 
                         Assun{\c{c}}{\~a}o Faus da and Nascimento, Ernani de Lima",
         englishtitle = "Squall lines in Southern Brazil",
             language = "pt",
                pages = "253",
                  ibi = "8JMKD3MGP3W34R/3R2P492",
                  url = "http://urlib.net/rep/8JMKD3MGP3W34R/3R2P492",
           targetfile = "publicacao.pdf",
        urlaccessdate = "29 nov. 2020"
}


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