TABLE OF CONTENTS The amount of energy dissipated during lightning flashes is an important parameter in many investigations involving lightning. It must be considered when characterising lightning flashes using their optical radiation from geostationary satellites and when quantifying the atmospheric production of ozone and nitrogen oxides etc. For example, the uncertainty involved in estimating the amount of NO x produced by lightning flashes can be attributed mainly to our poor knowledge about energy dissipation in lightning flashes. Unfortunately, it is not possible to measure the energy dissipated in a lightning flash directly. Consequently, researchers have employed indirect methods for this task. These methods can be divided into four categories. In the first category the amount of energy dissipated in lightning flashes is calculated on the basis of electrostatic energy considerations [166 171]. The energy dissipation is calculated by assuming that a known amount of charge is transferred across a known potential difference during the lightning flash. The potential of the thunder- cloud with respect to the earth is estimated by using familiar electrostatics principles. Table 4.19 summarises the results obtained by this method. In the second category the energy dissipation in lightning flashes is derived from the measured optical radiation [170,168,172,64 66]. In the analysis, experimentally obtained relationships between the electrical and optical energy in spark discharges were extrapolated to obtain the electrical energy dissipation in lightning flashes on the basis of the measured optical radiation. Table 4.20 summarises the results obtained. In the third...
