On theoretical approaches to estimate the lightning return stroke current parameters

The capability of several analytical equations to estimate the lightning channel base current parameters through measured fields, are discussed. The analytical equations derived from the Bruce and Golde model (1942), the Uman and McLain (1969) model, the Nucci et al. (1988) model, the Master et al. (1982) model and the Heidler (1985) model are capable of producing the peak current and the peak current derivative, at the channel base, once the measured remote electric field parameters are given. The current parameters estimated by Nucci et al. and Master et al. models are not much different from those estimations of the equation of the Uman and McLain model. The equations of the Deindorfer and Uman (1990) model and Thottappillil et al. (1991) model cannot be directly applied to estimate the peak current parameters in an analytical format. In a fast computer environment, it is very convenient and simple to employ a trial and error method to calculate the current parameters through measured electric fields and field derivatives, as proposed by Cooray and Gomes (1998)