The Stratiform Region of an MCS on 19 June in TELEX 2004 Observed With Polarimetric and Doppler Radars, Electric Field Soundings, and a Lightning Mapping Array
Abstract
Polarimetric and Doppler radar data, balloon-borne soundings of the electric field, and three-dimensional lightning mapping array data were acquired from a mesoscale convective system (MCS) on 19 June 2004 during the Thunderstorm Electrification and Lightning Experiment (TELEX). A total of 10 partial and complete vertical soundings through the storm were obtained from the flights of four instrumented balloons: two launched in the convective region, one in the transition zone, and one in the stratiform region. Each balloon recorded ascent and descent soundings and the transition zone balloon recorded an additional two partial soundings due to a downdraft. At times, multiple soundings were in progress simultaneously. This study focuses on the stratiform region of the MCS, which was sampled by the last two soundings of balloon three and both soundings of balloon four. A comparison of the electrical structure of the stratiform region of this MCS with that of previously published conceptual models suggests that, during at least part of the MCS's lifetime, its electrical structure was Type A, which is more complex than Type B. The main difference between these classifications is the number of charge regions in the cloud. A one-dimensional analysis with Gauss's law indicates six vertically stacked charge layers that alternated polarity within the stratiform region during balloon four's ascent. The vector electric field pattern verified the 1-D Gauss analysis and showed the electric field structure to be primarily horizontally stratified. The maximum magnitude of the electric field was approximately 105 kV/m. The second stratiform sounding sampled by balloon three began fifty minutes after the first stratiform sounding. It showed a very different electric field profile, consistent with neither Type A nor Type B electrical structure, perhaps because the sounding was far from the front of the MCS. There were only three charge layers as opposed to the four charge layers required by the classification scheme. The maximum electric field magnitude was approximately 75 kV/m. The remaining two stratiform soundings occurred after both of the previously mentioned soundings. The electrical structures inferred from these later soundings were even simpler, with only two charge layers in the cloud. The maximum electric field magnitudes were 50 kV/m and 75 kV/m. Charge layers inferred from the lightning structure observed by the Oklahoma Lightning Mapping Array correspond to charge layers seen in the electric field soundings. In addition, charge structure and lightning structure are examined relative to kinematic features from dual-Doppler radar analyses and relative to the distribution of various types of hydrometeors inferred from the polarimetric radar.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2005
- Bibcode:
- 2005AGUFMAE21A0977R
- Keywords:
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- 3304 Atmospheric electricity