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Correlation between the spectral features and electric field changes of multiple return strokes in negative cloud‐to‐ground lightning

Using high time‐resolved spectra and simultaneous records of the electric field change of three negative cloud‐to‐ground (CG) lightning flashes with multiple return strokes, the correlations between the total intensity of ionic lines in the spectra and the corresponding amplitude of the initial electric field change, as well as between the total intensity of the spectra and the channel apparent diameter, have been analyzed. The analysis shows the following: (1) The amplitude of the initial electric field change is roughly proportional to the total intensity of ionic lines. (2) The total intensity of the spectra shows a significant linear correlation with the apparent diameter of the channel. (3) The total intensity of ionic lines for 17 analyzed return strokes decreases with increasing height along the channel, which is consistent with the current variation along the channel in the modified transmission line model; the Master, Uman, Lin, and Standler model; and the Diendorfer‐Uman model. Meanwhile, the total intensity of ionic lines for other two analyzed return strokes along the channel without attenuation, this is consistent with the current variation along the channel in the Bruce‐Golde model, the transmission line model, and the Traveling Current Source model.