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| Titel |
Influence of ion attachment on the vertical distribution of the electric field and charge density below a thunderstorm |
| VerfasserIn |
X. Qie, S. Soula, S. Chauzy |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
0992-7689
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| Digitales Dokument |
URL |
| Erschienen |
In: Annales Geophysicae ; 12, no. 12 ; Nr. 12, no. 12, S.1218-1228 |
| Datensatznummer |
250011250
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| Publikation (Nr.) |
 copernicus.org/angeo-12-1218-1994.pdf |
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| Zusammenfassung |
| A numerical model called PICASSO [Production
d'Ions Corona Au Sol Sous Orage (French) and Production of Corona Ions at the
Ground Beneath Thundercloud (English)], previously designed, is used to describe
the evolution of the principal electrical parameters below a thunderstorm,
taking into account the major part played by corona ions. In order to improve
the model restitution of a real situation, various improvements are performed:
an initial vertical distribution of aerosol particles is introduced instead of
the previously used uniform concentration; time and space calculation steps are
adjusted according to the electric field variation rate; the upper boundary
condition is improved; and the coefficients of ion attachment are reconsidered
with an exhaustive bibliographic study. The influence of the ion attachment on
aerosol particles, on the electric field and charge density aloft, is studied by
using three different initial aerosol particle concentrations at ground level
and two types of initial vertical distributions: uniform and non-uniform. The
comparison between field data and model results leads to adjust the initial
aerosol particle concentration over the experimental site at the value of 5000
cm-3 which appears to be highly realistic. The evolutions of the
electric field and of the charge density at altitude are greatly influenced by
the aerosol concentration. On the contrary, the surface intrinsic field, defined
as the electric field that would exist underneath a thundercloud if there were
no local charges, is weakly affected when the model is forced by the surface
field. A good correlation appears between the success in the triggered lightning
attempts and this intrinsic field evaluation. Therefore, when only the surface
field is available, the model can be used in a triggered lightning experiment. |
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