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Simulation of the Universal-Time Diurnal Variation of the Global Electric Circuit Charging RateA global lightning model that includes diurnal and annual lightning variation, and total flash density versus latitude for each major land and ocean, has been used as the basis for simulating the global electric circuit charging rate. A particular objective has been to reconcile the difference in amplitude ratios [AR=(max-min)/mean] between global lightning diurnal variation (AR approx. = 0.8) and the diurnal variation of typical atmospheric potential gradient curves (AR approx. = 0.35). A constraint on the simulation is that the annual mean charging current should be about 1000 A. The global lightning model shows that negative ground flashes can contribute, at most, about 10-15% of the required current. For the purpose of the charging rate simulation, it was assumed that each ground flash contributes 5 C to the charging process. It was necessary to assume that all electrified clouds contribute to charging by means other than lightning, that the total flash rate can serve as an indirect indicator of the rate of charge transfer, and that oceanic electrified clouds contribute to charging even though they are relatively inefficient in producing lightning. It was also found necessary to add a diurnally invariant charging current component. By trial and error it was found that charging rate diurnal variation curves in Universal time (UT) could be produced with amplitude ratios and general shapes similar to those of the potential gradient diurnal variation curves measured over ocean and arctic regions during voyages of the Carnegie Institute research vessels.
Document ID
19990108761
Document Type
Conference Paper
Authors
Mackerras, D. (Queensland Univ. of Technology Brisbane, Australia)
Darvenzia, M. (Queensland Univ. of Technology Brisbane, Australia)
Orville, R. E. (Texas A&M Univ. College Station, TX United States)
Williams, E. R. (Massachusetts Inst. of Tech. Cambridge, MA United States)
Goodman, S. J. (NASA Marshall Space Flight Center Huntsville, AL United States)
Date Acquired
August 19, 2013
Publication Date
June 1, 1999
Publication Information
Publication: 11th International Conference on Atmospheric Electricity
Subject Category
Geophysics
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.
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