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| Titel |
Ice multiplication by mechanical breakup and lightning |
| VerfasserIn |
Vaughan Phillips, Jun-Ichi Yano |
| Konferenz |
EGU General Assembly 2016
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 18 (2016) |
| Datensatznummer |
250123119
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| Publikation (Nr.) |
 EGU/EGU2016-2318.pdf |
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| Zusammenfassung |
| Laboratory studies have proven the existence of several pathways for fragmentation of ice. One of these is the rime-splintering of graupel or hail in the -3 to -8 degC region (the Hallett-Mossop process). In some clouds, however, the cloud-base is too cold for this process to be active. Instead, breakup can occur by fragmentation of ice mechanically in re-bounding collisions between crystals, snow, graupel or hail.
A new theoretical formulation of this mechanical breakup process of multiplication is presented for these types of ice. A numerical scheme is derived by simulation of published laboratory experiments.
The role of such breakup in clouds is quantified by 3D simulations with a cloud-resolving aerosol-cloud model with emulated bin microphysics, detailed treatment of ice morphology and 7 chemical species of aerosol. Graupel-graupel collisions are predicted to produce copious numbers of ice crystals in the cold-base convective cloud simulated over Kansas.
Implications for lightning from such multiplication, also simulated numerically, are discussed. |
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