Spectral Analysis of Intracloud Lightning

Spectroscopy by method of camera-mounted slitless diffraction grating is an extremely useful research method. Previous studies have conducted spectral line tracing analyses on cloud-to-ground (CG) lightning return strokes using a spectrometer. To date, no spectral tracing analysis has been conducted on intracloud (IC) lightning flashes. As such, the current null holds that IC lightning channels and termination points contain physical properties similar to those of CG return stroke channels and termination points. In an effort to understand the physical behavior of IC lightning, specifically with respect to comparing the results of our work with existing literature on CG lightning, we utilized Nikon, Canon, and Lumix cameras, along with lens-mounted slitless diffraction gratings and MK Controls "Lightning Bug" IR sensors, to acquire visible-spectrum IC flash emission spectra. This poster's goal is twofold. First, we will demonstrate that our methods reproduce emission lines and emission line tracing analysis results expected from CG return strokes, as found in previous literature. Second, we will present our findings from spectral tracing analyses of IC lightning emission spectra that we obtained in the spring and summer of 2017. Our spectra will be used to, by previously established methods, determine the chemical composition, temperature, current and inductance of our sampled IC channels. Our findings will be used to compare the properties of IC lightning to those of CG return strokes, and we will discuss whether the null hypothesis, that the above physical properties are statistically similar in both CG and IC lightning, can be rejected.