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| Titel |
Influences from soluble and insoluble aerosols on precipitation and lightning in deep convection |
| VerfasserIn |
Vaughan Phillips, Marco Formenton, Barry Lienert |
| Konferenz |
EGU General Assembly 2013
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 15 (2013) |
| Datensatznummer |
250084065
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| Zusammenfassung |
| Observations reported in past studies in the literature have revealed correlations
between measures of aerosol loading and lightning occurrence. Recent advances in
simulating cloud-microphysical processes have highlighted their control by aerosol
conditions. New hypotheses about aerosol-precipitation-lightning interactions have
emerged.
Most deep convective clouds globally have warm bases with precipitation controlled by
coalescence and by loadings of soluble aerosols, which form droplets. However, those over
mountainous continental regions often have cooler bases and can generate much hail that
reaches the ground. Cold-base convective clouds were observed to produce lightning over the
High Plains of the USA during the Severe Thunderstorms Electrification and Precipitation
Study (STEPS) in the summer of 2000.
Cold-base thunderstorms can be without an active coalescence process, due to the low
adiabatic liquid water content limiting droplet sizes. There is then the potential for a greater
influence from ice-nucleating insoluble aerosols on ice-precipitation production, charge
separation and lightning, relative to soluble aerosols.
In the presentation, an aerosol-cloud model (hybrid bin/2-moment bulk microphysics,
prognostic aerosol component with 6 aerosol species) with a new electrification component is
described. The model treats non-inductive charge separation and has a lightning discharge
scheme. A simulation of a STEPS case of a cold-base thunderstorm is validated against
aircraft, radar and electrical observations.
Sensitivity tests are presented to show the roles of ice multiplication and ice-nucleating
aerosols, such as dust and soot from biomass-burning plumes, in controlling ice-precipitation
production and lightning frequencies for the cold-base thunderstorm. Their influence is
compared with that from soluble aerosol loadings. The roles of cloud-base temperature and
wet growth of hail and graupel are discussed. |
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