Extended Abstract (860K)10.3
Comparison of polarimetric algorithms for hydrometeor classification at S and C bands
Alexander V. Ryzhkov, CIMMS/Univ. of Oklahoma, Norman, OK; and D. S. Zrnic, P. Zhang, J. Krause, H. S. Park, D. Hudak, J. Young, J. L. Alford, M. Knight, and J. W. Conway
The paper contains description of the latest version of the hydrometeor classification algorithm (HCA) recommended for polarimetric prototype of the S-band WSR-88D radar and its adaptation for C band. The S-band version of HCA has been extensively tested in central Oklahoma (USA), whereas the C-band HCA was evaluated in Southern Ontario (Canada) and in Alabama (USA) for a number of storms of different types. Polarimetric observations at C band were made with the Environment Canada radar in King City, Ontario, and the EEC-built Sidpol radar in Alabama. Examined storm events include continental hailstorms, mesoscale convective systems, and tropical rain showers.
It is demonstrated that effects of resonance scattering at C band cause substantial differences in polarimetric characteristics of large hydrometeors between the two radar frequencies. The impact of resonance scattering is especially pronounced in hail-bearing storms. In the presence of large hydrometeors (e.g., big raindrops or melting hailstones), differential reflectivity at C band is higher than the one at S band for a given Z, whereas cross-correlation coefficient is lower at C band than at S band. As a result, the HDR technique for discrimination between rain and hail proven efficient at S band requires significant modification for application at C band.
Recommendations for adapting S-band membership functions in HCA for C band are substantiated by scattering model simulations and analysis of polarimetric measurements from a large and diverse set of weather events.
Session 10, Polarimetric Applications I
Thursday, 9 August 2007, 10:30 AM-12:30 PM, Hall A
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