Title :
Parameters of Electric Field Waveforms Produced by Positive Lightning Return Strokes
Author :
Nag, Avishek ; Rakov, V.A.
Author_Institution :
Dept. of Electr. & Comput. Eng., Univ. of Florida, Gainesville, FL, USA
Abstract :
In 2007-2008, 52 positive cloud-to-ground flashes containing 63 return strokes (52 first, 10 second, and 1 third) were recorded at the Lightning Observatory in Gainesville, Florida. The U.S. National Lightning Detection Network located 51 (96%) of the positive return strokes at distances of 7.8-157 km from the field measuring station and correctly identified 48 (91%) of them as cloud-to-ground discharges. In this study, parameters of positive return-stroke electric field and electric field derivative waveforms are examined. The geometric mean (GM) value of initial electric field peak normalized to 100 km for 48 strokes is 18 V/m. The GM peak electric field derivative normalized to 100 km for 27 strokes is 9.0 V/m/μs. The GM zero-to-peak risetime and 10-to-90% risetime for 62 strokes are 6.9 μs and 3.4 μs, respectively, and the GM slow front duration is 5.0 μs. The GM zero-crossing time for 42 strokes is 45 μs and the GM opposite polarity overshoot for 33 strokes is 13% of the peak. These characteristics are compared with those of negative return strokes in Florida found in the literature.
Keywords :
electric fields; lightning; lightning protection; waveform analysis; GM peak electric field derivative; GM zero crossing time; GM zero-to-peak risetime; cloud-to-ground discharge; cloud-to-ground flash; distance 7.8 km to 157 km; electric field derivative waveform; field measuring station; geometric mean value; polarity overshoot; positive lightning return stroke; Ash; Discharges (electric); Educational institutions; Electric fields; Electric variables measurement; Histograms; Lightning; Electric field; electric field derivative; positive lightning; return stroke; waveform parameters;
Journal_Title :
Electromagnetic Compatibility, IEEE Transactions on
DOI :
10.1109/TEMC.2013.2293628