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| Titel |
Relationship between level of neutral buoyancy and dual-Doppler observed mass detrainment levels in deep convection |
| VerfasserIn |
G. L. Mullendore, A. J. Homann, S. T. Jorgenson, T. J. Lang, S. A. Tessendorf |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1680-7316
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| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Chemistry and Physics ; 13, no. 1 ; Nr. 13, no. 1 (2013-01-08), S.181-190 |
| Datensatznummer |
250017545
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| Publikation (Nr.) |
 copernicus.org/acp-13-181-2013.pdf |
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| Zusammenfassung |
Although it is generally accepted that the level of neutral buoyancy (LNB) is
only a coarse estimate of updraft depth, the LNB is still used to understand
and predict storm structure in both observations and modeling. This study
uses case studies to quantify the variability associated with using
environmental soundings to predict detrainment levels. Nine dual-Doppler
convective cases were used to determine the observed level of maximum
detrainment (LMD) to compare with the LNB. The LNB for each case was
calculated with a variety of methods and with a variety of sources (including
both observed and simulated soundings). The most representative LNB was
chosen as the proximity sounding from NARR using the most unstable parcel and
including ice processes.
The observed cases were a mix of storm morphologies, including both supercell
and multicell storms. As expected, the LMD was generally below the LNB, the
mean offset for all cases being 2.2 km. However, there was a marked
difference between the supercell and non-supercell cases. The two supercell
cases had LMDs of 0.3 km and 0.0 km below the LNB. The remaining cases had
LMDs that ranged from 4.0 km below to 1.6 km below the LNB, with a mean
offset of 2.8 km below. Observations also showed that evolution of the LMD
over the lifetime of the storm can be significant (e.g., >2 km
altitude change in 30 min), and this time evolution is lacking from
models with coarse time steps, missing significant changes in detrainment
levels that may strongly impact the amount of boundary layer mass transported
to the upper troposphere and lower stratosphere. |
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