Polarimetric X-band weather radar measurements in the tropics: radome and rain attenuation correction

A polarimetric X-band radar has been deployed during one month (April 2011) for a field campaign in Fortaleza, Brazil, together with three additional laser disdrometers. The disdrometers are capable of measuring the raindrop size distributions (DSDs), hence making it possible to forward-model theore...

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Main Authors: M. Schneebeli, J. Sakuragi, T. Biscaro, C. F. Angelis, I. Carvalho da Costa, C. Morales, L. Baldini, L. A. T. Machado
Format: Article
Language:English
Published: Copernicus Publications 2012-09-01
Series:Atmospheric Measurement Techniques
Online Access:http://www.atmos-meas-tech.net/5/2183/2012/amt-5-2183-2012.pdf
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spelling doaj-9d6440400d1d4e2abf1926cef95b74492020-11-25T00:56:04ZengCopernicus PublicationsAtmospheric Measurement Techniques1867-13811867-85482012-09-01592183219910.5194/amt-5-2183-2012Polarimetric X-band weather radar measurements in the tropics: radome and rain attenuation correctionM. SchneebeliJ. SakuragiT. BiscaroC. F. AngelisI. Carvalho da CostaC. MoralesL. BaldiniL. A. T. MachadoA polarimetric X-band radar has been deployed during one month (April 2011) for a field campaign in Fortaleza, Brazil, together with three additional laser disdrometers. The disdrometers are capable of measuring the raindrop size distributions (DSDs), hence making it possible to forward-model theoretical polarimetric X-band radar observables at the point where the instruments are located. This set-up allows to thoroughly test the accuracy of the X-band radar measurements as well as the algorithms that are used to correct the radar data for radome and rain attenuation. For the campaign in Fortaleza it was found that radome attenuation dominantly affects the measurements. With an algorithm that is based on the self-consistency of the polarimetric observables, the radome induced reflectivity offset was estimated. Offset corrected measurements were then further corrected for rain attenuation with two different schemes. The performance of the post-processing steps was analyzed by comparing the data with disdrometer-inferred polarimetric variables that were measured at a distance of 20 km from the radar. Radome attenuation reached values up to 14 dB which was found to be consistent with an empirical radome attenuation vs. rain intensity relation that was previously developed for the same radar type. In contrast to previous work, our results suggest that radome attenuation should be estimated individually for every view direction of the radar in order to obtain homogenous reflectivity fields.http://www.atmos-meas-tech.net/5/2183/2012/amt-5-2183-2012.pdf
collection DOAJ
language English
format Article
sources DOAJ
author M. Schneebeli
J. Sakuragi
T. Biscaro
C. F. Angelis
I. Carvalho da Costa
C. Morales
L. Baldini
L. A. T. Machado
spellingShingle M. Schneebeli
J. Sakuragi
T. Biscaro
C. F. Angelis
I. Carvalho da Costa
C. Morales
L. Baldini
L. A. T. Machado
Polarimetric X-band weather radar measurements in the tropics: radome and rain attenuation correction
Atmospheric Measurement Techniques
author_facet M. Schneebeli
J. Sakuragi
T. Biscaro
C. F. Angelis
I. Carvalho da Costa
C. Morales
L. Baldini
L. A. T. Machado
author_sort M. Schneebeli
title Polarimetric X-band weather radar measurements in the tropics: radome and rain attenuation correction
title_short Polarimetric X-band weather radar measurements in the tropics: radome and rain attenuation correction
title_full Polarimetric X-band weather radar measurements in the tropics: radome and rain attenuation correction
title_fullStr Polarimetric X-band weather radar measurements in the tropics: radome and rain attenuation correction
title_full_unstemmed Polarimetric X-band weather radar measurements in the tropics: radome and rain attenuation correction
title_sort polarimetric x-band weather radar measurements in the tropics: radome and rain attenuation correction
publisher Copernicus Publications
series Atmospheric Measurement Techniques
issn 1867-1381
1867-8548
publishDate 2012-09-01
description A polarimetric X-band radar has been deployed during one month (April 2011) for a field campaign in Fortaleza, Brazil, together with three additional laser disdrometers. The disdrometers are capable of measuring the raindrop size distributions (DSDs), hence making it possible to forward-model theoretical polarimetric X-band radar observables at the point where the instruments are located. This set-up allows to thoroughly test the accuracy of the X-band radar measurements as well as the algorithms that are used to correct the radar data for radome and rain attenuation. For the campaign in Fortaleza it was found that radome attenuation dominantly affects the measurements. With an algorithm that is based on the self-consistency of the polarimetric observables, the radome induced reflectivity offset was estimated. Offset corrected measurements were then further corrected for rain attenuation with two different schemes. The performance of the post-processing steps was analyzed by comparing the data with disdrometer-inferred polarimetric variables that were measured at a distance of 20 km from the radar. Radome attenuation reached values up to 14 dB which was found to be consistent with an empirical radome attenuation vs. rain intensity relation that was previously developed for the same radar type. In contrast to previous work, our results suggest that radome attenuation should be estimated individually for every view direction of the radar in order to obtain homogenous reflectivity fields.
url http://www.atmos-meas-tech.net/5/2183/2012/amt-5-2183-2012.pdf
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