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| Titel |
Detection of potentially hazardous convective clouds with a dual-polarized C-band radar |
| VerfasserIn |
A. Adachi, T. Kobayashi, H. Yamauchi, S. Onogi |
| 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 ; 6, no. 10 ; Nr. 6, no. 10 (2013-10-21), S.2741-2760 |
| Datensatznummer |
250085087
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| Publikation (Nr.) |
 copernicus.org/amt-6-2741-2013.pdf |
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| Zusammenfassung |
A method for forecasting very short-term rainfall to detect potentially
hazardous convective cloud that produces heavy local rainfall was developed
using actual volumetric C-band polarimetric radar data. Because the rainfall
estimation algorithm used in this method removed the effect of ice particles
based on polarimetric measurements, it was immune to the high reflectivity
associated with hail. The reliability of the algorithm was confirmed by
comparing the rainfall rate estimated from the polarimetric radar
measurements at the lowest elevation angle with that obtained from optical
disdrometers on the ground. The rainfall rate estimated from polarimetric
data agreed well with the results obtained from the disdrometers, and was
much more reliable than results derived from reflectivity alone.
Two small cumulus cells were analyzed, one of which developed and later
produced heavy rainfall, whereas the other did not. Observations made by
polarimetric radar with a volumetric scan revealed that a high vertical
maximum intensity of rainfall rate and a vertical area of enhanced
differential reflectivity extending above the freezing level, often termed a
high ZDR column, were clearly formed about 10 min prior to the onset
of heavy rainfall on the ground. The onset time of the heavy rainfall could
be estimated in advance from the polarimetric data, which agreed fairly well
with observations. These polarimetric characteristics were not observed for
the cumulus cell that did not produce heavy rainfall. The results suggest
that both the vertical maximum intensity of the rainfall rate and a high
ZDR column, estimated from polarimetric measurements, can be used to
identify potentially hazardous clouds. Furthermore, this study shows that
polarimetric radar measurements with high spatial and temporal resolutions
are invaluable for disaster reduction. |
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