1991 Volume 111 Issue 1 Pages 63-68
A lightning strength parameter, α, (denoted as LSP or LAIDO) which is used for characterizing the phenomena of lightning activity has been proposed, where, α is defined by the characteristic energy obtained from the distribution function of a radiation field component, Er, in the electric field changes produced by lightning discharges. Here, that the energy distribution of Er, component has Maxwellian type has been observed.
In order to proof more clearly the abovementioned assumption from the other point of view a change of amplitude of the electrostatic field component, Es, has been measured to make distribution functions.
In the cloud-to-ground lightning discharges, Es component has been observed to show positive sign in the changes, but in the inner-cloud discharges it shows either negative or positive change depending on the distance between the striking point and the observation site. Therefore, it is necessary to sum up the number of occurrences of both positive and negative components for making a energy distribution of Es, component.
When the change of the Es component has been measured, both a fieldmill and a pair of doughnut shaped static antenna are employed. It is shown as a result that the change of the amplitude of Es, component has a Maxwellian type energy distribution. Then, we have defined a characteristic energy β obtained from the electrostatic component as also a measure of LSP.
After comparing α with β, it is clarified that the β has the same characteristic nature with α, and the lightning activity could be estimated from β.