Polarimetric Attenuation Correction in Heavy Rain at C Band

Abstract

The ability of C-band polarimetric radar to account for strong attenuation/differential attenuation is demonstrated in two cases of heavy rain that occurred in the Chicago, Illinois, metropolitan area on 5 August 2008 and in central Oklahoma on 10 March 2009. The performance of the polarimetric attenuation correction scheme that separates relative contributions of ''hot spots'' (i.e., strong convective cells) and the rest of the storm to the path-integrated total and differential attenuation has been explored. It is shown that reliable attenuation correction is possible if the radar signal is attenuated by as much as 40 dB. Examination of the experimentally derived statistics of the ratios of specific attenuation A h and differential attenuation A DP to specific differential phase K DP in hot spots is included in this study. It is shown that these ratios at C band are highly variable within the hot spots. Validation of the attenuation correction algorithm at C band has been performed through cross-checking with S-band radar measurements that were much less affected by attenuation. In the case of the Oklahoma storm, a comparison was made between the data collected by closely located C-band and S-band polarimetric radars.

A Dual-Wavelength Polarimetric Analysis of the 16 May 2010 Oklahoma City Extreme Hailstorm

“…The first direct comparisons of polarimetric hail signatures observed by closely located S-and C-band radars (Borowska et al 2011;Gu et al 2011) are generally consistent with results of these theoretical simulations.…”

“…despite generally corrupted measurements of differential phase at C band, it was possible to manually retrieve radial profiles of F DP along selected radials. Tabary et al (2009b) and Gu et al (2011) demonstrate that differential attenuation increases dramatically in the presence of large raindrops manifesting themselves as very high Z DR at the near side of the hotspot, as is the case for the radial at 3518. This explains extremely strong differential attenuation along the ray.…”

“…One of the possible solutions is utilizing the so-called hotspot correction method described in Gu et al (2011). This method restores reasonably well the radial profiles of attenuated Z at C band, Z(C) (see reflectivity curves in Fig.…”

“…and 0.01-0.03 dB (8) 21 , respectively (e.g., Gu et al 2011). The total spans of F DP at 3468 and 3518 are 598 and 988, respectively, and simple linear attenuation correction would yield much lower values of DZ and DZ DR than the ones shown in Fig.…”

Observations of the 10 May 2010 Tornado Outbreak Using OU-PRIME: Potential for New Science with High-Resolution Polarimetric Radar

“…In partnership with Enterprise Electronics Corporation (EEC), OU embarked on the development of the OU Polarimetric Radar for Innovations in Meteorology and Engineering (OU-PRIME) facility, which was commissioned on 4 April 2009. Initial work with OU-PRIME has focused on comparative, multiple-wavelength studies exploiting other independent radars in Norman (e.g., Picca and Ryzhkov 2010;Borowska et al 2011;Gu et al 2011) and the development and implementation of advanced signal processing algorithms (Wang et al 2008;Lei et al 2009;Warde and Torres 2010).…”