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@InProceedings{SaraivaCaAlPiZeBu:2014:EsReLe,
               author = "Saraiva, Ant{\^o}nio Carlos V. and Campos, Leandro Zanella de 
                         Souza and Alves, J{\'e}ferson and Pinto Jr., Osmar and Zepka, 
                         Gisele dos Santos and Buzato, Tiago Santos",
          affiliation = "{Instituto Nacional de Pesquisas Espaciais (INPE)} and {Instituto 
                         Nacional de Pesquisas Espaciais (INPE)} and {Instituto Nacional de 
                         Pesquisas Espaciais (INPE)} and {Instituto Nacional de Pesquisas 
                         Espaciais (INPE)} and {Instituto Nacional de Pesquisas Espaciais 
                         (INPE)} and {Instituto Nacional de Pesquisas Espaciais (INPE)}",
                title = "Estimates of recoil leaders peak currents based on high-speed 
                         video observations",
            booktitle = "Proceedings...",
                 year = "2014",
         organization = "International Lightning Detection Conference, 23. (ILDC); and 
                         International Lightning Meteorology Conference, 5 (ILMC).",
            publisher = "Vaisala",
                 note = "Informa{\c{c}}{\~o}es Adicionais: During the summer season of 
                         2012, a network of high-speed cameras, called RAMMER network, 
                         recorded two bipolar flashes produced by a thunderstorm that 
                         occurred on March 13th. Data from BrasilDAT network provided 
                         location and peak current information for the events. Additional 
                         RAW data from the sensors, allowed more detailed analyses. Both 
                         bipolar flashes presented multiple negative return strokes, and 
                         there was intense recoil leader activity bellow cloud base. The 
                         objective of this work is the evaluation of the peak currents of 
                         those recoil leaders. The bipolar nature of these flashes allowed 
                         a unique way to calibrate the camera luminosity with the stroke 
                         peak currents estimated by the local lightning location system 
                         (LLS). Recoil leaders are commonly visible below cloud base during 
                         positive flashes development, but have not yet been observed 
                         during negative flashes in a similar fashion. The bipolar flashes 
                         observed had one positive return stroke and multiple negative 
                         return strokes that were used in the calibration process. In order 
                         to evaluate the recoil leaders peak current, the luminosity levels 
                         of each video were calibrated using the unsaturated pixel 
                         brightness levels during the negative return strokes and the data 
                         from the BrasilDAT LLS. The same high-speed camera used during the 
                         observation campaign was tested in laboratory to determine its 
                         CMOS sensor response curve. Through a scatter diagram of 
                         luminosity (estimated from the pixel intensity values) versus 
                         estimated peak current (provided by the BrasilDAT network), it was 
                         shown that both physical quantities are related. The calibrated 
                         pixel values were used to create equations to calculate the recoil 
                         leader peak currents. A total of 281 recoil leaders were 
                         identified, 191 in flash #1 and 90 in flash #2. Results show that 
                         recoil leader estimates are closely related to previous 
                         observations of cloud discharges by LLS. The geometric mean value 
                         was 1.06 kA, with a maximum of 7.7 kA. Less than 14% presented 
                         peak.",
             keywords = "atmospheric electricity, recoil leaders, high-speed video 
                         observations, lightning.",
             abstract = "During the summer season of 2012, a network of high-speed cameras, 
                         called RAMMER network, recorded two bipolar flashes produced by a 
                         thunderstorm that occurred on March 13th. Data from BrasilDAT 
                         network provided location and peak current information for the 
                         events. Additional RAW data from the sensors, allowed more 
                         detailed analyses. Both bipolar flashes presented multiple 
                         negative return strokes, and there was intense recoil leader 
                         activity bellow cloud base. The objective of this work is the 
                         evaluation of the peak currents of those recoil leaders. The 
                         bipolar nature of these flashes allowed a unique way to calibrate 
                         the camera luminosity with the stroke peak currents estimated by 
                         the local lightning location system (LLS). Recoil leaders are 
                         commonly visible below cloud base during positive flashes 
                         development, but have not yet been observed during negative 
                         flashes in a similar fashion. The bipolar flashes observed had one 
                         positive return stroke and multiple negative return strokes that 
                         were used in the calibration process. In order to evaluate the 
                         recoil leaders peak current, the luminosity levels of each video 
                         were calibrated using the unsaturated pixel brightness levels 
                         during the negative return strokes and the data from the BrasilDAT 
                         LLS. The same high-speed camera used during the observation 
                         campaign was tested in laboratory to determine its CMOS sensor 
                         response curve. Through a scatter diagram of luminosity (estimated 
                         from the pixel intensity values) versus estimated peak current 
                         (provided by the BrasilDAT network), it was shown that both 
                         physical quantities are related. The calibrated pixel values were 
                         used to create equations to calculate the recoil leader peak 
                         currents. A total of 281 recoil leaders were identified, 191 in 
                         flash #1 and 90 in flash #2. Results show that recoil leader 
                         estimates are closely related to previous observations of cloud 
                         discharges by LLS. The geometric mean value was 1.06 kA, with a 
                         maximum of 7.7 kA. Less than 14% presented peak currents 
                         comparable to weak return strokes (> 2 kA).",
  conference-location = "Tucson",
      conference-year = "mar. 18-19, 2014 / mar. 20-21, 2014",
                label = "lattes: 4161737266837399 2 SaraivaCaAlPiZeBu:2014:EsReLe",
             language = "en",
           targetfile = "Saraiva et al-Estimates of recoil leader peak currents based on 
                         high-speed video observations-2014-ILDC-ILMC.pdf",
                  url = "http://www.vaisala.com/en/events/ildcilmc/Documents/2014%20ILDC-ILMC%20Agenda.pdf",
               volume = "1",
        urlaccessdate = "28 mar. 2024"
}


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