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| Titel |
The exchange across the tropical tropopause in overshooting convective cores |
| VerfasserIn |
T. N. Rao, B. Radhakrishna, T. Mohan Satyanarayana, S. Satheesh Kumar |
| 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 ; 28, no. 1 ; Nr. 28, no. 1 (2010-01-18), S.113-122 |
| Datensatznummer |
250016747
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| Publikation (Nr.) |
 copernicus.org/angeo-28-113-2010.pdf |
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| Zusammenfassung |
| Coordinated measurements of Indian MST radar and radiosonde during the
passage of overshooting convective cores in SAFAR pilot campaign
(May–November 2008) are utilized to quantify the mass flux across the
tropopause and strength of the turbulence in up- and down-draft cores. The
distribution of retrieved mass flux is found to be wide, ranging from −0.6
(downward flux) to 0.8 kg m−2 s−1 (upward flux). The net mass
flux, is, however, from the troposphere to stratosphere, in spite of the
existence of significant amount of downward flux. For the first time, the
turbulence strength in the vicinity of the tropopause in convective cores is
quantified. Large spectral widths with magnitudes >4 m s−1 are
observed during convection. However, such large spectral widths are rare and
are observed only for 1.6% of total observations. The average spectral
width (and also the variation or standard deviation) in draft cores is found
to be ~4.5 times larger than that in fair-weather. The turbulence
strength in updraft cores is much higher than that of in downdraft cores.
The mean (median) spectral width in updraft cores is larger by ~0.8 m s−1
(a factor of ~2) than that of in downdraft cores. The
turbulence strength does not show any systematic variation with the
intensity of convection in both up- and down-draft cores. The distributions
and mean values of mass flux and turbulence strength obtained in the present
study will be useful to quantify the STE due to direct intrusion of mass by
overshooting convection and the exchange of constituents (in particular
water vapor) due to turbulence in a better way. |
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