Evaluation of multiple ground flash charge structure from electric field measurements using the local lightning detection network in the region of Warsaw

During three summer months from 16 June to 16 September 2009, the Local Lightning Detection Network (LLDN) set up in the Warsaw region was successfully operated. Seventeen events of multiple cloud-to-ground (CG) lightning flashes have been recognized which caused E-field variations recorded simultaneously by all the LLDN six stations. A dedicated software package has been developed for the purpose of the E-field analysis and calculations of the three-dimensional location of the lightning point electric charge source. The location has been determined by the source coordinates x, y, z in a local Cartesian coordinate system and besides the magnitude of the electric charge, Q, involved in a CG return stroke or continuing current, has been obtained. Several examples of the spatial and temporal development of the multiple CG flashes initiated in different meteorological situations are presented and discussed in the paper.