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Characterizing Charge Structure in Central Argentina Thunderstorms During RELAMPAGO Utilizing a New Charge Layer Polarity Identification Method
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  • Bruno L. Medina,
  • Lawrence D. Carey,
  • Timothy J Lang,
  • Phillip M. Bitzer,
  • Wiebke Deierling,
  • Yanan Zhu
Bruno L. Medina
The University of Alabama in Huntsville, The University of Alabama in Huntsville

Corresponding Author:[email protected]

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Lawrence D. Carey
The University of Alabama in Huntsville, The University of Alabama in Huntsville
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Timothy J Lang
NASA MSFC, NASA MSFC
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Phillip M. Bitzer
University of Alabama in Huntsville, University of Alabama in Huntsville
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Wiebke Deierling
University of Colorado Boulder, University of Colorado Boulder
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Yanan Zhu
University of Alamaba in Huntsville, University of Alamaba in Huntsville
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Abstract

A new automated method to retrieve charge layer polarity from flashes, named Chargepol, is presented in this paper. Using data from the NASA Lightning Mapping Array (LMA) deployed during the RELAMPAGO field campaign in Cordoba, Argentina, from November 2018 to April 2019, this method estimates the polarity of vertical charge distributions and their altitudes and thicknesses (or vertical depth) using the very-high frequency (VHF) source emissions detected by LMAs. When this method is applied to LMA data for extended periods of time, it is capable of inferring a storm’s bulk electrical charge structure throughout its life cycle. This method reliably predicted the polarity of charge within which lightning flashes propagated and was validated in comparison to methods that require manual assignment of polarities via visual inspection of VHF lightning sources. Examples of normal and anomalous charge structures retrieved using Chargepol for storms in Central Argentina during RELAMPAGO are presented for the first time. Application of Chargepol to five months of LMA data in Central Argentina and several locations in the United States allowed for the characterization of the charge structure in these regions and for a reliable comparison using the same methodology. About 13.3% of Cordoba thunderstorms were defined by an anomalous charge structure, slightly higher than in Oklahoma (12.5%) and West Texas (11.1%), higher than Alabama (7.3%), and considerably lower than in Colorado (82.6%). Some of the Cordoba anomalous thunderstorms presented enhanced low-level positive charge, a feature rarely if ever observed in Colorado thunderstorms.