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| Titel |
Rain microstructure retrievals using 2-D video disdrometer and C-band polarimetric radar |
| VerfasserIn |
M. Thurai, V. N. Bringi, W. A. Petersen |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1680-7340
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| Digitales Dokument |
URL |
| Erschienen |
In: Observation, Prediction and Verification of Precipitation (EGU Session 2008) ; Nr. 20 (2009-03-12), S.13-18 |
| Datensatznummer |
250014329
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| Publikation (Nr.) |
 copernicus.org/adgeo-20-13-2009.pdf |
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| Zusammenfassung |
| Measurements using the 2-D video disdrometer (2DVD) taken during a heavy
rainfall event in Huntsville, Alabama, are analysed. The 2DVD images were
processed to derive the rain microstructure parameters for each individual
drop, which in turn were used as input to the T-matrix method to compute the
forward and back scatter amplitudes of each drop at C-band. The polarimetric
radar variables were then calculated from the individual drop contribution
over a finite time period, e.g., 1 min. The calculated co-polar
reflectivity, differential reflectivity, specific differential propagation
phase and the co-polar correlation coefficient were compared with
measurements from a C-band polarimetric radar located 15 km away. An
attenuation-correction method based on the specific differential propagation
phase was applied to the co-polar and differential reflectivity data from
the C-band radar, after ensuring accurate radar calibration. Time series
comparisons of the parameters derived from the 2DVD and C-band radar data
show very good agreement for all four quantities, the agreement being
sometimes better than the computations using the 1-min drop size
distribution and bulk assumptions on rain microstructure (such as mean
shapes and model-based assumptions for drop orientation). The agreement is
particularly improved in the case of co-polar correlation coefficient since
this parameter is very sensitive to variation of shapes as well as
orientation angles. The calculations mark the first attempt at utilizing
experimentally derived "drop- by-drop" rain microstructure information to
compute the radar polarimetric parameters and to demonstrate the value of
utilizing the 2-D video disdrometer for studying rain microstructure under
various precipitation conditions. Histograms of drop orientation angles as
well as the most probable drop shapes and the corresponding variations were
also derived and compared with prior results from the 80 m fall "artificial
rain" experiment. |
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