%0 Journal Article
%@archivingpolicy denypublisher denyfinaldraft24
%3 Atmosph.Research.pdf
%4 sid.inpe.br/mtc-m18@80/2008/11.21.13.18
%@issn 0169-8095
%A Campos, Leandro Zanella de Souza,
%A Saba, Marcelo Magalhães Fares,
%A Pinto Júnior, Osmar,
%A Ballarotti, Maurício Grade,
%@secondarytype PRE PI
%B Atmospheric Research
%D 2009
%F self-archiving-INPE-MCTIC-GOV-BR
%@secondarykey INPE--PRE/
%K Continuing current waveshapes, M-components, Positive lightning, High-speed video.
%P 416-424
%@secondarymark B1_ENGENHARIAS_II A2_GEOCIÊNCIAS A1_INTERDISCIPLINAR
%T Waveshapes of continuing currents and properties of M-components in natural positive cloud-to-ground lightning
%V 91
%X This work analyses the waveshapes of continuing currents and parameters of M-components in positive cloud-to-ground (CG) flashes through high-speed GPS synchronized videos. The dataset is composed of only long continuing currents (with duration longer than 40 ms) and was selected from more than 800 flashes recorded in São José dos Campos (45.864°W, 23.215°S) and Uruguaiana (29.806°W, 57.005°S) in Southeast and South of Brazil, respectively, during 2003 to 2007 summers. The videos are compared with data obtained by the Brazilian Lightning Location System (BrasilDAT) in order to determine the polarity of each flash and select only positive cases. There are only two studies of waveshapes of continuing currents in the literature. One is based on direct current measurements of triggered lightning, in which four different types of waveshapes were observed; and the other is based on measurements of luminosity variations in high-speed videos of CG negative lightning, in which besides the four types above mentioned two additional types were observed. The present work is an extension of the latter, using the same method but now applied to obtain the waveshapes of positive CG lightning. As far as the authors know, this is the first report on M-components in positive continuing currents. We also have used the luminosity-versus-time graphs to observe their occurrence and measure some parameters (duration, elapsed time and time between two successive M-components), whose statistics are presented and compared in detail to the data for negative flashes. We have plotted a histogram of the M-components elapsed time over the total duration of the continuing current for positive flashes, which presented an exponential decay (correlation coefficient: 0.83), similar to what has been observed for negative flashes.
%@area CEA
%@documentstage not transferred
%@group DGE-CEA-INPE-MCT-BR
%@group DGE-CEA-INPE-MCT-BR
%@group DGE-CEA-INPE-MCT-BR
%@group DGE-CEA-INPE-MCT-BR
%@dissemination WEBSCI; PORTALCAPES.
%@usergroup administrator
%@usergroup simone
%@nexthigherunit 8JMKD3MGPCW/3EU29DP
%@affiliation Instituto Nacional de Pesquisas Espaciais (INPE)
%@affiliation Instituto Nacional de Pesquisas Espaciais (INPE)
%@affiliation Instituto Nacional de Pesquisas Espaciais (INPE)
%@affiliation Instituto Nacional de Pesquisas Espaciais (INPE)
%@versiontype publisher
%@holdercode {isadg {BR SPINPE} ibi 8JMKD3MGPCW/3DT298S}
%@doi 10.1016/j.atmosres.2008.02.020
%2 sid.inpe.br/mtc-m18@80/2008/11.21.13.18.14