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| Titel |
The role of conditional symmetric instability in Sting Jet storms |
| VerfasserIn |
L. H. Baker, O. Martínez-Alvarado, S. L. Gray, P. A. Clark |
| Konferenz |
EGU General Assembly 2009
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 11 (2009) |
| Datensatznummer |
250025890
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| Zusammenfassung |
| The aim of this project is to determine the mechanisms that lead to sting jets in extreme
windstorms and develop diagnostics for predicting their formation and development.
Extratropical cyclones often produce strong surface winds, mostly associated with
low-level jets along the warm and cold fronts. Some severe extratropical cyclones
have been found to produce an additional area of localised strong, and potentially
very damaging, surface winds during a certain part of their development. These
strong winds are associated with air that originates within the cloud head, exiting at
the tip of the cloud head and descending rapidly from there to the surface. This
rapidly descending air associated with the strong surface winds is known as a sting
jet.
One significant feature of sting jet storms is mesoscale slantwise circulations in the cloud
head, which have been speculated to be due to the release of conditional symmetric instability
(CSI). Analyses of two very different proposed sting jet storms will be presented. In both
cases, a sting jet feature has been identified and examined using two diagnostics for CSI:
SCAPE (slantwise convective available potential energy) and moist potential vorticity
(MPV). SCAPE and negative MPV exist near the tip of the cloud heads and SCAPE
decreases during the time of the descent of the sting jets, indicating that CSI may be being
released. |
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