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| Titel |
Mesoscale convection system and occurrence of extreme low tropopause temperatures: observations over Asian summer monsoon region |
| VerfasserIn |
A. R. Jain, V. Panwar, T. K. Mandal, V. R. Rao, A. Goel, R. Gautam, S. S. Das, S. K. Dhaka |
| 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. 4 ; Nr. 28, no. 4 (2010-04-12), S.927-940 |
| Datensatznummer |
250016815
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| Publikation (Nr.) |
 copernicus.org/angeo-28-927-2010.pdf |
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| Zusammenfassung |
| The present study examines the process of how tropospheric air enters the
stratosphere, particularly in association with tropical mesoscale convective
systems (TMCS) which are considered to be one of the causative mechanisms
for the observation of extremely low tropopause temperature over the
tropics. The association between the phenomena of convection and the
observation of extreme low tropopause temperature events is, therefore,
examined over the Asian monsoon region using data from multiple platforms.
Satellite observations show that the area of low outgoing long wave
radiation (OLR), which is a proxy for the enhanced convection, is embedded
with high altitude clouds top temperatures (≤193 K). A detailed
analysis of OLR and 100 hPa temperature shows that both are modulated by
westward propagating Rossby waves with a period of ~15 days,
indicating a close linkage between them. The process by which the
tropospheric air enters the stratosphere may, in turn, be determined by how
the areas of convection and low tropopause temperature (LTT) i.e. T≤191 K
are spatially located. In this context, the relative spatial
distribution of low OLR and LTT areas is examined. Though, the locations of
low OLR and LTT are noticed in the same broad area, the two do not always
overlap, except for partial overlap in some cases. When there are multiple
low OLR areas, the LTT area generally appears in between the low OLR areas.
Implications of these observations are also discussed. The present analysis
also shows that the horizontal mean winds have a role in the spatial
distribution of low OLR and LTT. |
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