A comparative study of negative cloud-to-ground lightning characteristics in São Paulo (Brazil) and Arizona (United States) based on high-speed video observations

• Published in: Journal of Geophysical Research. D. Atmospheres Vol. 115; no. D11
• Main Authors: Saraiva, A. C. V., Saba, M. M. F., Pinto Jr, O., Cummins, K. L., Krider, E. P., Campos, L. Z. S.
• Format: Journal Article
• Language: English
• Published: Washington, DC Blackwell Publishing Ltd 16-06-2010; American Geophysical Union
• Subjects: Atmospheric sciences; characteristics; Climate change; Comparative studies; Earth; Earth sciences; Earth, ocean, space; Exact sciences and technology; Geophysics; Instrumentation; Lightning; Statistical analysis; Thunderstorms; South America; Brazil; United States; Sao Paulo Brazil; Arizona; USA, Arizona; Brazil, Sao Paulo; Ground discharge; climate; clouds; Thunderstorm; North America; duration; currents; instruments; Lightning; Multiplicity; statistical analysis; Comparative study; storms; Atmospheric electricity
• ISSN: 0148-0227; 2169-897X; 2156-2202; 2169-8996
• DOI: 10.1029/2009JD012604

There are only a few prior reports that detail accurate measurements of the number of strokes in natural negative cloud‐to‐ground (CG) lightning flashes. These are known as “accurate‐stroke‐count” studies, and they have been performed using various instruments and techniques. Here, we will examine the lightning characteristics produced by warm‐season thunderstorms in two different climate regimes (southern Arizona, United States, and São Paulo, Brazil) using the same instrumentation. The lightning parameters were obtained from high‐speed video recordings and time‐correlated data provided by lightning locating systems (LLS). The use of these instruments has allowed us to measure the number of strokes in each flash and their polarity, the interstroke intervals, the number of different ground contacts, and the durations of the continuing currents. Altogether 209 negative flashes were recorded on video in the United States and 223 in Brazil (containing a total of 1681 strokes), and the majority of these flashes had at least one stroke reported by a LLS. Statistical analyses of these data sets as a whole did not show any significant differences in the characteristics of negative CG flashes from warm‐season thunderstorms in both locations. The mean values for all data are as follows: video multiplicity, 3.9; single‐stroke flashes, 19.5%; flash duration, 226.5 ms; interstroke interval, 61.5 ms; long continuing current, 17.5%; multigrounded flashes, 49.5%. Those characteristics were very similar to the well‐accepted values for negative flashes in other regions. However, there were large storm‐to‐storm variations.