The accuracy of acoustic reconstructions of lightning channels

Abstract

The effects of wave front curvature, wind, and temperature on the determination of the direction of propagation of thunder at an array of microphones is examined, and it is shown that the direction of propagation can be measured at the array with an error of less than ±1° under the following conditions: the wind velocity at the array should be measured with an accuracy of ±1 m/s, the temperature at the array with an accuracy of ±2°C, and the range to the source with an accuracy of ±20%. The positions of the source points on the lightning channel, which represent the total lightning event at that location, are mapped by acoustic ray tracing techniques; this procedure requires information on the temperature and wind velocity as a function of altitude; without this information and in adverse conditions, errors of 10% for high-altitude sources and 25% for sources near the horizon will occur. By using supportive data on wind and temperature profiles all error estimates can be reduced to 5%, which is more than sufficient to do comparative studies of lightning channel structures inside clouds with the macrophysical properties of the clouds.