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Return stroke velocity measurements in multistroke lightning flashes

1976; American Geophysical Union; Volume: 81; Issue: 24 Linguagem: Inglês

10.1029/jc081i024p04461

2156-2202

James S. Boyle, Richard E. Orville,

Fire effects on ecosystems

Journal of Geophysical Research (1896-1977)Volume 81, Issue 24 p. 4461-4466 Meteorology Return stroke velocity measurements in multistroke lightning flashes James S. Boyle, James S. BoyleSearch for more papers by this authorRichard E. Orville, Richard E. OrvilleSearch for more papers by this author James S. Boyle, James S. BoyleSearch for more papers by this authorRichard E. Orville, Richard E. OrvilleSearch for more papers by this author First published: 20 August 1976 https://doi.org/10.1029/JC081i024p04461Citations: 40AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onEmailFacebookTwitterLinkedInRedditWechat Abstract A multislit channel isolator with narrow vertical and wide horizontal fields of view has been used on a high-speed streaking camera to measure two-dimensional return stroke velocities within 1 km of the ground. The slits serve to isolate small vertical sections of the return stroke channel of the order of tens of meters. The isolated sections in the object plane are separated by a vertical distance of the order of a few hundred meters. Data are obtained at a writing rate of 8.5×104 mm s−1 with a time resolution of 2.3 μs.All film was calibrated for the emulsion's nonlinear response to light. Measurements of 12 strokes in three multistroke flashes yield return stroke velocities which range from 2×107 to 12×107 m S−1 with an estimated systematic error which varies from 30 to 60%. Velocities in one multistroke flash vary by a factor of 4 between the lowest and highest values. A higher relative intensity was detected in the upper parts of the channel relative to the lower. This may reflect the greater excitation of neutral atomic species in the upper channel and is a characteristic of lightning photographs obtained with red extended photographic emulsions. References Flowers, J. W., Lightning … measuring lightning currents photographically, procedure and examples of results, Gen. Elec. Rev., 47, 9–15, 1944. Hagenuth, J. H., Photographic study of lightning, AIEE Trans., 66, 577–585, 1947. Krider, E. P., G. Marcek, A simplified technique for the photography of lightning in daylight, J. Geophys. Res., 77, 6017–6020, 1972. McEachron, K. B., New England lightning checks African studies, Elec. World, 15–16, 1934. McEachron, K. B., Lightning to the Empire State Building, J. Franklin Inst., 227, 149–217, 1939. Orville, R. E., A high-speed time-resolved spectroscopic study of the lightning return stroke, 1, 2, and 3, J. Atmos. Sci., 255, 827–856, 1968. Orville, R. E., Spectrum of the lightning dart leader, J. Atmos. Sci., 32, 1829–1837, 1975. Orville, R. E., J. H. Helsdon Jr., W. H. Evans, Quantitative analysis of a lightning return stroke for diameter and luminosity changes as a function of space and time, J. Geophys. Res., 79, 4059–4067, 1974. Radda, G. J., E. P. Krider, Photoelectric measurements of lightning return stroke propagation speeds (abstract), Eos Trans. AGU, 55, 1131, 1974. Salanave, L. E., R. E. Orville, C. N. Richards, Slitless spectra of lightning in the region from 3850 to 6900 angstroms, J. Geophys. Res., 67, 1877–1884, 1962. Schonland, B. F. J., H. Collens, Progressive lightning, Proc. Roy. Soc. London, Ser. A, 143, 654–674, 1934. Schonland, B. F. J., D. J. Malan, H. Collens, Progressive lightning, 2, Proc. Roy. Soc. London, Ser. A, 168, 455–469, 1935. Uman, M. A., R. D. Brantley, Y. T. Lin, J. A. Tiller, E. P. Krider, D. K. McLain, Correlated electric and magnetic fields from lightning return strokes, J. Geophys. Res., 80, 373–376, 1975. Citing Literature Volume81, Issue24Oceans and Atmospheres20 August 1976Pages 4461-4466 ReferencesRelatedInformation