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| Titel |
Role of convection in hydration of tropical UTLS: implication of AURA MLS long-term observations |
| VerfasserIn |
S. Jain, A. R. Jain, T. K. Mandal |
| 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 ; 31, no. 5 ; Nr. 31, no. 5 (2013-05-24), S.967-981 |
| Datensatznummer |
250019044
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| Publikation (Nr.) |
 copernicus.org/angeo-31-967-2013.pdf |
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| Zusammenfassung |
This paper addresses various characteristic features associated with the
hydration of the tropical upper troposphere and lower stratosphere (UTLS) in
association with the boreal monsoonal convective activity occurring over
three different tropical regions viz. Asian region, American region and
African region. Analysis of water vapor mixing ratio (WVMR) data obtained from AURA MLS (v3.3),
ISCCP D1 cloud top pressure data and outgoing long-wave radiation data (OLR)
from NOAA reanalysis has brought out two significant results. Firstly, high
altitude clouds and high WVMR regions are mostly
associated with the low OLR region. Convection over Asian region is very
deep and spread over a large geographical area as compared to African or
American region. Magnitude of WVMR in the pressure range of 261.0–146.8 hPa
is observed to be higher over the Asian region, whereas, close to the
tropopause level (~ 100 hPa) it is comparable or more over the
American region as compared to Asian and African regions. Secondly, the
vertical ascent rate of water vapour obtained from AURA MLS data suggest that
convection associated transport might have dominated up to 146.8–121.2 hPa
in addition to slow large scale diabatic transport, which appears to be
prominent above the pressure range of 100–82.5 hPa. Within the pressure
levels of 121.2 to 82.5 hPa, the influence of convective transport appears
to be gradually decreasing. However, there are other possible processes like
ice sublimation or cirrus jumping which could contribute to the hydration of
the tropical lower stratosphere. Present analysis has, thus, brought out the
significance of convection in water vapour transport and distribution in the
tropical UTLS.
Another interesting feature which is observed is the anomalous increase in
temperature during boreal winters (November–April) over all three convective
regions. Such phenomenon is only observed within the pressure range of
100.0–261.0 hPa; however it is relatively weaker for levels > 177.8 hPa. |
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