Lightning Mapping Observations in North Colorado during DC3

A 15-station Lightning Mapping Array (LMA) was operated in northern Colorado during DC3 that provided detailed observations both of individual discharges and of the overall lightning activity in electrified storms. The mapping network was about 100 km in diameter and provided good quality coverage out to several hundred km range from the CHILL radar site. A surprising variety of electrical structures in terms of lightning source altitudes and polarities were observed that would potentially affect chemical production processes. In addition, some of the storms investigated by the G-V and DC8 may have had their electrical structure altered by ingestion of smoke from major forest fires that occurred over the front range. A basic but potentially useful metric of the overall lightning activity related to chemical production will be the total number of VHF radiation sources per given time interval, empirically weighted by source alitude, peak radiated power, and radiation duration. Also, 50 kHz-sampled lightning electric field change measurements were continuously recorded at two sites during the study period that will provide quantitative information on the number of high-current, impulsive events such as ground return strokes and in-cloud K-changes that are also important in chemical processes. These and other potentially important aspects the lightning observations will be discussed.