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Titel |
Properties of rainfall in a tropical volcanic island deduced from UHF wind profiler measurements |
VerfasserIn |
A. Réchou, T. Narayana Rao, O. Bousquet, M. Plu, R. Decoupes |
Medientyp |
Artikel
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Sprache |
Englisch
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ISSN |
1867-1381
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Digitales Dokument |
URL |
Erschienen |
In: Atmospheric Measurement Techniques ; 7, no. 2 ; Nr. 7, no. 2 (2014-02-07), S.409-418 |
Datensatznummer |
250115594
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Publikation (Nr.) |
copernicus.org/amt-7-409-2014.pdf |
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Zusammenfassung |
The microphysical properties of rainfall at the island of Réunion are analysed
and quantified according to one year of wind profiler observations collected
at Saint-Denis international airport. The statistical analysis clearly shows
important differences in rain vertical profiles as a function of the seasons.
During the dry season, the vertical structure of precipitation is driven by
trade wind and boundary-layer inversions, both of which limit the vertical
extension of the clouds. The rain rate is lower than 2.5 mm h−1
throughout the lower part of the troposphere (about 2 km) and decreases in
the higher altitudes. During the moist season, the average rain rate is
around 5 mm h−1 and nearly uniform from the ground up to 4 km.
The dynamical and microphysical properties (including drop size
distributions) of four distinct rainfall events are also investigated
through the analysis of four case studies representative of the variety of
rain events occurring on Réunion: summer deep convection,
northerly-to-northeasterly flow atmospheric pattern, cold front and winter
depression embedded in trade winds. Radar-derived rain parameters are in
good agreement with those obtained from collocated rain gauge observations
in all cases, which demonstrates that accurate qualitative and quantitative
analysis can be inferred from wind profiler data. Fluxes of kinetic energy
are also estimated from wind profiler observations in order to evaluate the
impact of rainfall on soil erosion. Results show that horizontal kinetic
energy fluxes are systematically one order of magnitude higher than vertical
kinetic energy fluxes. A simple relationship between the reflectivity factor
and vertical kinetic energy fluxes is proposed based on the results of the
four case studies. |
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