Lightning imaging with thunder using broadband direction-of-arrival estimation technique

A single-station-based three-dimensional (3D) acoustic lighting mapping system comprising a microphone array has been developed and used for lightning observations, in which a new broadband direction-of-arrival (DOA) estimation techniques namely incoherent signal-subspace method are proposed for thunder signals in the far-field. Two cloud-to-ground (CG) flashes with highly branch channels recorded by the system are analyzed and presented in this paper. The acoustic mapping results can not only locate on the main channel produced by the return stroke process but also depict the branch channels. Moreover, the located thunder sources by the mapping system and the photography of the high speed camera agree well with each other demonstrating the effectiveness and correctness of the estimation techniques and the mapping system.