Busca avançada
Ano de início
Entree
(Referência obtida automaticamente do Web of Science, por meio da informação sobre o financiamento pela FAPESP e o número do processo correspondente, incluída na publicação pelos autores.)

High-speed video and electromagnetic analysis of two natural bipolar cloud-to-ground lightning flashes

Texto completo
Autor(es):
Mostrar menos -
Saraiva, A. C. V. [1] ; Campos, L. Z. S. [1] ; Williams, E. R. [2] ; Zepka, G. S. [1] ; Alves, J. [1] ; Pinto, Jr., O. [1] ; Heckman, S. [3] ; Buzato, T. S. [1] ; Bailey, J. C. [4] ; Morales, C. A. [5] ; Blakeslee, R. J. [6]
Número total de Autores: 11
Afiliação do(s) autor(es):
[1] Natl Inst Space Res, Sao Jose Dos Campos - Brazil
[2] MIT, Dept Civil & Environm Engn, Cambridge, MA 02139 - USA
[3] Earth Networks, Germantown, MD - USA
[4] Univ Alabama, Earth Syst Sci Ctr, Huntsville, AL 35899 - USA
[5] Univ Sao Paulo, Inst Astron Geofis & Ciencias Atmosfer, Sao Paulo - Brazil
[6] NASA Marshall Space Flight Ctr, Huntsville, AL - USA
Número total de Afiliações: 6
Tipo de documento: Artigo Científico
Fonte: JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES; v. 119, n. 10, p. 6105-6127, MAY 27 2014.
Citações Web of Science: 16
Resumo

High-speed video records of two bipolar cloud-to-ground flashes were analyzed in detail. They both began with a single positive return stroke that was followed by more than one subsequent weak negative stroke. Due to the elevated cloud base height of its parent thunderstorm, the preparatory processes of each subsequent negative stroke were documented optically below cloud base. In the first event (Case 1) it was observed that all four subsequent negative strokes were initiated by recoil leaders that retraced one horizontal channel segment previously ionized by the positive leader. Those recoil leaders connected to the original vertical channel segment and propagated toward ground, producing four subsequent strokes that had the same ground contact point as the original positive discharge. The second event (Case 2), in contrast, presented 15 subsequent strokes that were initiated by recoil leaders that did not reach the original channel of the positive stroke. They diverged vertically toward ground, making contact approximately 11 km away from the original positive strike point. These results constitute the first optical evidence that both single-and multiple-channel bipolar flashes occur as a consequence of recoil leader activity in the branches of the initial positive return stroke. For both events their total channel length increased continuously at a rate of the order of 10(4) m s(-1), comparable to speeds reported for typical positive leaders. (AU)

Processo FAPESP: 08/56711-4 - Detecção de sinais de variabilidade relacionados a mudanças climáticas na incidência de descargas atmosféricas no Brasil
Beneficiário:Osmar Pinto Junior
Linha de fomento: Auxílio à Pesquisa - Temático
Processo FAPESP: 10/01742-2 - Rede automatizada multi-câmeras para o monitoramento e estudo de raios (projeto RAMMER)
Beneficiário:Antonio Carlos Varela Saraiva
Linha de fomento: Bolsas no Brasil - Pós-Doutorado
Processo FAPESP: 09/15235-8 - Processos de nuvens associados aos principais sistemas precipitantes no Brasil: uma contribuição à modelagem da escala de nuvens e ao GPM (Medida Global de Precipitação)
Beneficiário:Luiz Augusto Toledo Machado
Linha de fomento: Auxílio à Pesquisa - Temático