Additional analyses of possibly inverted-polarity electrical structures in thunderstorms during STEPS

We first showed preliminary evidence of possibly inverted-polarity electrical structures in thunderstorms at the AGU Fall meeting in 2000. The evidence that such might exist came from the polarity of peaks in the profile of the vertical component of the electric field and inferred charge structures using a one-dimensional form of Gauss's law. These were compared to typical (i.e., noninverted) conceptual models of storm structure. Realizing the uncertainties from use of these techniques, we have been exploring additional ways to help determine the gross electrical structure of thunderstorms. The data sets from STEPS offer two additional sources for inferring charge regions: the lightning mapping array and three-dimensional vector analysis of the electric field profiles. At the time this abstract was due, analyses of four possibly inverted-polarity electrical structures in the convective region were underway. The analysis thus far from one storm strongly suggests that it had an inverted-polarity electrical structure. The assessment of all four candidate electrical structures will be presented at the meeting.