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TITULOCloud-to-ground lightning and Mesoscale Convective Systems
Acessar
ID2
Autor(es)Enrique V. Mattos
TipoArtigo/Matéria de jornal
PublicadoAtmospheric Research
Data da publicação2011
Instituição
CategoriasLightning Mesoscale Convective System Cloud microphysics Nowcasting
Link permanentehttps://meteorologia.unifei.edu.br/artigos/?id=2
Citação
ResumoThis work analyzes some physical and microphysical properties of Mesoscale Convective Systems (MCSs) and cloud-to-ground lightning. Satellite data from the GOES-10 infrared and NOAA-18 and TRMM microwave channels and lightning information from the Brazilian lightning detection network (BrasilDAT) were utilized for the period from 2007 to 2009. Based on an automatic MCSs detection method, 720 MCSs life cycles were identified during the period and in the region of study, with a lightning detection efficiency of over 90%. During the diurnal cycle, maximum electrical activity occurred close to the time of maximum convective cloud fraction (18 UTC), and 3 h after the maximum normalized area expansion rate. Diurnal cycles of both properties were modulated by diurnal heating, and thus could be used to monitor diurnal variability of lightning occurrence. The electrical activity was more intense for the widest (Pearson’s correlation of 0.96) and deeper (Pearson’s correlation of 0.84) clouds, which reached 390 km size and 17 km maximum cloud top height. Area growth during the initial phase of MCSs exerted a strong influence on their size and duration, and thus also showed a potential for defining the possibility of electrical activity during their life cycle. The average lightning life cycle exhibited a maximum close to MCSs maturation, while the maximum average lightning density occurred in the MCSs initial life cycle stage. The growth rate of electrical activity during the early stages can indicate the strength of convection and the possible duration of systems with lightning occurrence. Strong condensation processes and mass flux during the growth phase of the systems can provide favorable conditions for cloud electrification and lightning occurrence. A comparison of high microwave frequencies with lightning data showed a strong relationship of vertically integrated ice content and particle size with lightning occurrence, with Pearson's correlation of 0.86 and 0.96, respectively. The polarization difference in the 85 GHz channel showed that electrical activity increases linearly with polarization reduction, associated with a high value of Pearson's correlation coefficient (above 0.90). This suggests that regions with more intense electrical activity are predominantly located in areas with a high concentration of larger ice particles that are vertically oriented, due to the existence of intense updrafts and the electric field. These results demonstrate the potential use of thermodynamic, dynamic and microphysical characteristics for analyzing thunderstorms severity, and as additional information for nowcasting and monitoring electrical activity over large regions that lack ground-based lightning sensors.



TITULOIMPLANTAÇÃO E OPERAÇÃO DE UM SISTEMA DE MONITORAMENTO E ALERTA HIDROMETEOROLÓGICO PARA O ALTO RIO SAPUCAÍ (MG)
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ID3
Autor(es)Benedito Cláudio da Silva, Michelle Simões Reboita, GABRIEL DE OLIVEIRA MACHADO, Camila Coelho Welerson, Christie André de Souza, João Tarcísio de Oliveira Júnior
Tipooutros
PublicadoXXIII SBRH - Simpósio Brasileiro de Recursos Híd
Data da publicaçãonov/2019
InstituiçãoUNIFEI
CategoriasMonitoramento hidrometeorológico, Rio Sapucaí, Itajubá
Link permanentehttps://meteorologia.unifei.edu.br/artigos/?id=3
Citação
ResumoEste trabalho apresenta uma descrição e os resultados parciais de um sistema de monitoramento e alerta hidrológico e meteorológico da bacia hidrográfica do AltoRioSapucaí. Osistema foi planejado e implementado com foco em gerar previsões e alertas para a cidade de Itajubá (MG), que possui um longo histórico de inundações emsua área urbana.Atualmente possui um conjuntode estações automáticas que monitoram toda área da bacia a montante de Itajubá em intervalos de tempo horário, possibilitando acompanhar em tempo real a situação de seus principais rios. Modelos de previsão estão sendo implantados e todos os dados e prognósticos serão disponibilizadosem uma página na internet, que já possui uma versão preliminar emoperação.Muitas são as dificuldades encontradas,principalmente em relação a recursos, mas o sistema já está emoperação e estará sempre em contínuo aprimoramento.



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