author = "Ribeiro, Bruno Zanetti and Seluchi, Marcelo E.",
          affiliation = "{Instituto Nacional de Pesquisas Espaciais (INPE)} and {Centro 
                         Nacional de Monitoramento e Alertas de Desastres Naturais 
                title = "A climatology of quasi-linear convective systems and 
                         associatedsynoptic-scale environments in southern Brazil",
              journal = "International Journal of Climatology",
                 year = "2018",
               volume = "2018",
                pages = "1--21",
             keywords = "quasi-linear convective systems, severe thunderstorms, southern 
                         Brazil, synopticclimatology.",
             abstract = "This study presents a 9-year climatology and composite analysis of 
                         quasi-linearconvective systems (QLCSs) in southern Brazil (SB). 
                         QLCSs are identified usingradar imagery and defined as a 100-km 
                         long, 40-dBZ convective line that lasts forat least 1 hr. QLCS 
                         cases associated with at least three severe wind reports are 
                         clas-sified as severe. Composites of the synoptic-scale 
                         environments and severe convec-tive weather parameters are 
                         constructed for severe and non-severe cases of threesynoptic 
                         patterns found as the most recurrent in QLCS cases. QLCSs are more 
                         fre-quent and more likely to be severe during spring, while very 
                         few cases occur dur-ing winter. Most cases occur during late night 
                         and morning, corroborating previousresearch of mesoscale 
                         convective systems in this area, but the percentages of 
                         severecases are higher in late afternoon and early night. Faster 
                         QLCSs, particularly thosewith velocities greater than 50 km/hr, 
                         have higher probability of being severe incomparison to slower 
                         systems. The three synoptic patterns more often related toQLCS 
                         occurrence in SB are characterized by a mid-level trough upstream 
                         of SB(type 1), a mid-level trough west of the Andes (type 2) and 
                         predominance of zonalflow over SB (type 3). In general, there is a 
                         low-pressure system over northwesternArgentina extending a trough 
                         to SB, where low-level moisture flux convergenceand warm advection 
                         occur. In severe cases, the sea-level pressure is lower in 
                         north-western Argentina and there is greater low-level 
                         northwesterly flow over SB. Thetype 1 is the most frequent pattern 
                         when QLCSs are observed in SB and is also thetype with higher 
                         percentage of severe cases. Convective available potential 
                         energy(CAPE) and downdraft CAPE are good discriminators between 
                         severe and non-severe cases in type 1 and 2 environments, while 
                         the 1,000500-hPa bulk wind dif-ference is a better predictor in 
                         type 3 cases.",
                  doi = "10.1002/joc.5847",
                  url = "http://dx.doi.org/10.1002/joc.5847",
                 issn = "0899-8418",
             language = "en",
           targetfile = "ribeiro_climatology.pdf",
        urlaccessdate = "25 jul. 2021"