Digital High-Speed Spectroscopic Recordings in the Upward Lightning Triggering Study (UPLIGHTS)

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This is a three-year project for field operations divided into two parts. The first two years, 2013 and 2014, will be a field program in Rapid City, South Dakota followed by evaluation and analyses. The third year, 2015, will be the appropriate time to use two high-speed cameras (one for spectra; one for black and white imagery) at the Camp Blanding, University of Florida experimental station. Three spectroscopic optical input diffraction grating units, two with gratings blazed at 560 nm and 600 nm, and one at 750 nm have also be built in the previous years. The objective of the current research is to obtain spectral data (380 - 850 nm) from the entire optical channel length with high time resolution for all visible elements, i.e. return strokes, stepped and dart leaders, M-strokes, continuing currents, and recoil leaders associated with positive and negative leader breakdown. These spectral data will provide estimates of temperature, electron density, and other thermodynamic properties throughout the channel lengths. In addition, these data will then be matched to National Lightning Detection Network (NLDN) and Lightning Mapping Array (LMA) or interferometry measurements on the same flashes for which the polarity, peak current, flash extent, etc. can be derived. This total information will provide the most complete physical description of natural and triggered lightning channels to-date.Intellectual Merit: The intellectual merit of this research activity is to provide the most complete physical description of natural and triggered lightning channels to-date.Broader Impact: Results from the research will have an immediate impact on the research programs of cooperating scientists and their students. At the moment, more than ten cooperating institutions have expressed an interest in the Lightning Project and the associated information. This research will contribute to the education of graduate students who will directly participate in the project. Research results will be incorporated into advanced courses on cloud physics and mesoscale phenomena.