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| Titel |
Effect of tropical cyclones on the tropical tropopause parameters observed using COSMIC GPS RO data |
| VerfasserIn |
S. Ravindra Babu, M. Venkat Ratnam, G. Basha, B. V. Krishnamurthy, B. Venkateswararao |
| 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 ; 15, no. 18 ; Nr. 15, no. 18 (2015-09-16), S.10239-10249 |
| Datensatznummer |
250120033
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| Publikation (Nr.) |
 copernicus.org/acp-15-10239-2015.pdf |
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| Zusammenfassung |
| Tropical cyclones (TCs) are deep convective synoptic-scale systems that play
an important role in modifying the thermal structure, tropical tropopause
parameters and hence also modify stratosphere–troposphere exchange (STE) processes. In
the present study, high vertical resolution and high accuracy measurements
from COSMIC Global Positioning System (GPS) radio occultation (RO)
measurements are used to investigate and quantify the effect of tropical
cyclones that occurred over Bay of Bengal and Arabian Sea in the last decade on
the tropical tropopause parameters. The tropopause parameters include cold-point
tropopause altitude (CPH) and temperature (CPT), lapse-rate tropopause
altitude (LRH) and temperature (LRT) and the thickness of the tropical
tropopause layer (TTL), that is defined as the layer between convective
outflow level (COH) and CPH, obtained from GPS RO data. From all the TC
events, we generate the mean cyclone-centred composite structure for the
tropopause parameters and removed it from the climatological mean obtained from
averaging the GPS RO data from 2002 to 2013. Since the TCs include eye, eye
walls and deep convective bands, we obtained the tropopause parameters based
on radial distance from the cyclone eye. In general, decrease in the CPH in the
eye is noticed as expected. However, as the distance from the cyclone eye
increases by 300, 400, and 500 km, an enhancement in CPH (CPT) and LRH (LRT)
is observed. Lowering of CPH (0.6 km) and LRH (0.4 km) values with coldest CPT
and LRT (2–3 K) within a 500 km radius of the TC centre is noticed.
Higher (2 km) COH leading to the lowering of TTL thickness (2–3 km) is
clearly observed. There are multiple tropopause structures in the profiles
of temperature obtained within 100 km from the centre of the TC. These changes in
the tropopause parameters are expected to influence the water vapour
transport from the troposphere to the lower stratosphere, and ozone from the lower
stratosphere to the upper troposphere, hence influencing STE processes. |
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