Estimation of Lightning Stroke Peak Current as a Function of Peak Electric Field and the Normalized Amplitude of Signal Strength: Corrections and Improvements

Corrections and improvements have been made to published equations relating return stroke peak current and peak electric field for cloud-to-ground lightning. The original equations were derived from measurements made at the Rocket-Triggered-Lightning Program facility at the Kennedy Space Center in Florida. Some previous articles include errors in the conversion of equations from units of volts per meter, for peak electric field, into Lightning Location and Protection units, representing normalized signal strength amplitude. This article presents the proper conversion procedure and the resultant corrected equations. Furthermore, equations are presented that were produced by converting other published relationships. Finally, we combined 1985--1988 RTLP data to produce equations based on more data than has been used previously; the resulting equation for peak current as a function of normalized signal strength amplitude supports previous evidence that the slope should be near 0.2 for a zero intercept. All relationships are tabulated, and three are graphically compared against the data.