Estimate of NOx production in the lightning channel based on three-dimensional lightning locating system

Based on the VHF lightning locating system, a three-dimensional-space cell-gridded approach is used to extract the lighting channel and calculate the length of the channel. Through clustering of the located radiation sources and then extracting the lightning channel, it can accurately obtain the length of the channel. To validate the feasibility of the approach, a simulation experiment is designed, and it shows the length error is no more than 10%. The relationship between the NO production of per unit arc length and atmospheric pressure obtained in laboratory is applied to the NOx production of per unit flash length at different altitudes in this paper. The channel length and the NOx production of 11 negative cloud-to-ground flashes and 59 intracloud flashes in an isolated thunderstorm in the northeastern Qinghai-Tibet Plateau are calculated. The results show that the average channel lengths of per cloud-to-ground and intracloud flash are 28.9 and 22.3 km respectively; the average NOx productions of per cloud-to-ground and intracloud flash are 1.89× 10^25 and 0.42× 10^25 molecules, respectively.