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

Autor(es)

Schneebeli, M. ^{[1, 2]} ; Sakuragi, J. ^[1] ; Biscaro, T. ^[1] ; Angelis, C. F. ^[1] ; Carvalho da Costa, I. ^[1] ; Morales, C. ^[3] ; Baldini, L. ^[4] ; Machado, L. A. T. ^[1]

Afiliação do(s) autor(es)

^[1] CPTEC, INPE, Cachoeira Paulista - Brazil

^[2] Ecole Polytech Fed Lausanne, Sch Architecture Civil & Environm Engn ENAC, CH-1015 Lausanne - Switzerland

^[3] Univ Sao Paulo, Inst Astron Geofis & Ciencias Atmosfer, Sao Paulo - Brazil

^[4] Inst Sci Atmosfera & Clima CNR, Rome - Italy

• Tipo de documento: Artigo Científico
• Fonte: Atmospheric Measurement Techniques; v. 5, n. 9, p. 2183-2199, 2012.
• Citações Web of Science: 18

Resumo

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 setup 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. (AU)

• Processo FAPESP: 09/15235-8 - Processos de nuvens associados aos principais sistemas precipitantes no Brasil: uma contribuição à modelagem da escala de nuvens e ao GPM (Medida Global de Precipitação)
• Beneficiário: Luiz Augusto Toledo Machado
• Linha de fomento: Auxílio à Pesquisa - Temático