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Total lightning characteristics of ordinary convection

Twenty-two isolated, non-severe, warm season thunderstorms (ordinary
thunderstorms) were examined to test possible correlations between three-dimensional
lightning flash characteristics and the complex evolution of the microphysical and
kinematic processes involved in the electrical development of thunderstorms. Nine of the
thunderstorm cases examined occurred within range of Vaisala Inc.'s Dallas-Fort Worth
(DFW) Lightning Detection and Ranging (LDAR) network and the other thirteen cases
occurred within range of the Texas A&M University Houston LDAR Network. Cloud-toground
(CG) flash data were obtained from the National Lightning Detection Network
(NLDN). The kinematic and microphysical properties of each convective cell were
inferred from level II Weather Surveillance Radar 1988-Doppler data.
Lightning properties were compared to radar reflectivity, Vertically Integrated
Liquid, Severe Hail Index, and Vertically Integrated Ice (VII) (i.e. the measure of the
precipitation ice water content in and above the mixed phase (-40°C < T < -10° C zone).
In addition, total lightning (intra-cloud (IC) and CG) characteristics were compared
against CG lightning characteristics to determine if total lightning data provide stronger
correlations to convective intensity and state (i.e., developing, mature, dissipating) than
CG lightning data alone. The results show that VII is well correlated to the total flash rate with r2 values of
0.45 and 0.81 for Houston and Dallas cases, respectively, whereas CG flashes show much
weaker correlations to VII. The cases also follow the conventional model of lightning
within ordinary storms with IC dominating over CG lightning in the initial stages of
convective development. An average of 19 IC flashes occur before the first CG flash with
an average lead-time between the first IC to the first CG of 12 minutes. Flash heights
showed little correlation to VII, which is in disagreement with past studies suggesting
that strong correlations exist between flash heights and storm intensity.
Integration of the results from this study into an operational forecast setting could
lead to improvements in the nowcasting of lightning threats using radar, numerical
weather prediction via assimilation of total lightning data, and the nowcasting of severe
weather and lightning hazards to aviation.
Date02 June 2009
CreatorsMotley, Shane Michael
ContributorsCarey, Larry
Source SetsTexas A and M University
Detected LanguageEnglish
TypeBook, Thesis, Electronic Thesis, text
Formatelectronic, application/pdf, born digital

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