HR: 1340h
AN: AE23A-0831    [Abstracts]
TI: Triggered Lightning in Brazil: First Results
AU: * Solorzano, N N
EM: natalia@dge.inpe.br
AF: University of Washington, Department of Earth and Space Sciences, Box 351310, Seattle, WA 98195-1310 United States
AU: * Solorzano, N N
EM: natalia@dge.inpe.br
AF: INPE (Instituto Nacional de Pesquisas Espaciais), Avenida dos Astronautas, 1758, Sao Jose dos Campos, SP 12227-010 Brazil
AU: Pinto, O
EM: osmar@dge.inpe.br
AF: INPE (Instituto Nacional de Pesquisas Espaciais), Avenida dos Astronautas, 1758, Sao Jose dos Campos, SP 12227-010 Brazil
AU: Saba, M M
EM: msaba@dge.inpe.br
AF: INPE (Instituto Nacional de Pesquisas Espaciais), Avenida dos Astronautas, 1758, Sao Jose dos Campos, SP 12227-010 Brazil
AU: Eybert-Berard, A
EM: andre.eybert-berard @ libertysurf.fr
AF: Indelec, 61 chemin des Postes, Douai, 59500 France
AB: Two induction techniques using rocket-and-wire systems were applied at the International Center for Natural and Triggered Lightning Studies (CIPRIN) in Brazil: (i) the classical method, which involves a conductive trailing wire connected to the ground and (ii) the altitude method, with an ungrounded wire. The artificial initiation of atmospheric discharges was conducted for the first time in tropical latitudes (S~$22^041.2^{\prime}$; W $44^059.0^{\prime}$; altitude: $625$~m). The $4$ campaigns analyzed in this work occurred during the summers of $2000$ to $2003$, resulting in $41$ rocket flights with success rates of $45%$ and $27%$ for the classical and the altitude techniques, respectively. Coaxial shunts, an optical sensor, electric field antennas and a high speed camera were used for characterizing the current waveforms of the classical strokes. Simultaneous results on current, luminosity and electric field, accompanied by high-speed camera images were obtained for the first time for an altitude flash. In addition, the peak currents of the strokes were determined using data from the shunts and compared to measurements from magnetic cards. The Brazilian Integrated Network (BIN), ground-based sensors that cover the southeastern area of Brazil, detected $54%$ of the triggered flashes. Compared to both artificial lightning observations performed in other countries and natural strokes detected by the BIN during the induced events, there was a tendency for peak currents to be generally higher for triggered lightning at CIPRIN . Moreover, the current pulses of the induced strokes observed in Brazil were faster than pulses measured in other sites. The higher peak currents and faster pulses observed at CIPRIN resulted in similar values of charge transferred per stroke compared to data obtained by other sites. However, more triggering experiments at CIPRIN are needed to provide better statistical results.
DE: 3324 Lightning
DE: 3304 Atmospheric electricity
SC: Atmospheric and Space Electricity [AE]
MN: 2004 AGU Fall Meeting