ESTIMATION OF LIGHTNING-STROKE PEAK CURRENT AS A FUNCTION OF PEAK ELECTRIC-FIELD AND THE NORMALIZED AMPLITUDE OF SIGNAL STRENGTH - CORRECTIONS AND IMPROVEMENTS

The authors have made corrections and improvements to published equati ons relating the peak current and the peak electric field intensity fo r return strokes of cloud-to-ground lightning. The original published equations were derived from measurements of rocket-wire-triggered ligh tning made at the Rocker-Triggered-Lightning Program (RTLP) Facility a t the Kennedy Space Center in Florida. Previous articles published by others included errors in the conversion of the equations from volts p er meter (for peak electric field), to a proportional quantity, LLP (l ightning location and protection units), representing range-normalized signal strength amplitude. The proper conversion procedure and the re sultant corrected equations are presented in this paper. Also presente d are equations produced by converting other published relationships. The authors combined rocket-triggered-lightning data for 1985-91 from the RTLP facility to produce a regression equation of peak current and range-normalized signal strength amplitude (in LLP units) based on a larger dataset than previous investigators used. The resulting equatio n supports the conclusion from theoretical work that the peak current varies with range-normalized signal strength amplitude to give a slope of 0.2 for a zero intercept. Most of the regression equations in the text are tabulated; three are compared graphically.