Effects of atmospheric attenuation on lightning spectrum

Spectrum carries important information reflecting atomic and molecular processes inside light source. Accurate spectral diagnosis is of vital significance in revealing microscopic physical mechanism of lightning discharge process. Aimed at the problems of atmospheric attenuation in long-distance lightning spectrum observations, considering the influence of atmospheric attenuation, grating efficiency and camera response on the observed spectrum, the spectral correction is carried out in this work. Based on the restored spectrum, the temperature of core current-carrying channel and the mean temperature of the luminous channel were calculated respectively. The result showed that the corrected temperature of core current-carrying channel at initial stage of return stroke could reach up to 40000 K, which was about 10000 K higher than the value directly obtained from observed spectrum. In addition, there is a steep temperature gradient between the core current-carrying channel and its peripheral hot channel. This work provided the attenuation ratio of the characteristic lines in lightning spectra with distance which is could be used for more precisely quantitative investigation on physical characteristic of lightning process, and it also has application value for improving the spectral diagnostic techniques on celestial body and other natural luminous process.