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| Titel |
Impact of land convection on temperature diurnal variation in the tropical lower stratosphere inferred from COSMIC GPS radio occultations |
| VerfasserIn |
S. M. Khaykin, J.-P. Pommereau, A. Hauchecorne |
| 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. 13 ; Nr. 13, no. 13 (2013-07-05), S.6391-6402 |
| Datensatznummer |
250018740
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| Publikation (Nr.) |
 copernicus.org/acp-13-6391-2013.pdf |
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| Zusammenfassung |
| Following recent studies evidencing the influence of deep convection on the
chemical composition and thermal structure of the tropical lower
stratosphere, we explore its impact on the temperature diurnal variation in
the upper troposphere and lower stratosphere using the high-resolution
COSMIC GPS radio-occultation temperature measurements spanning from 2006
through 2011. The temperature in the lowermost stratosphere over land during
summer displays a marked diurnal cycle characterized by an afternoon
cooling. This diurnal cycle is shown collocated with most intense land
convective areas observed by the Tropical Rainfall Measurement Mission
(TRMM) precipitation radar and in phase with the maximum overshooting
occurrence frequency in late afternoon. Two processes potentially
responsible for that are identified: (i) non-migrating tides, whose physical
nature is internal gravity waves, and (ii) local cross-tropopause mass
transport of adiabatically cooled air by overshooting turrets. Although both
processes can contribute, only the lofting of adiabatically cooled air is
well captured by models, making it difficult to characterize the contribution
of non-migrating tides. The impact of deep convection on the temperature
diurnal cycle is found larger in the southern tropics, suggesting more
vigorous convection over clean rain forest continents than desert areas and
polluted continents in the northern tropics. |
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