Session 5.5 Comparison of polarimetric radar observations of tornadic supercells at S, C, and X bands

Monday, 27 October 2008: 8:45 PM
North & Center Ballroom (Hilton DeSoto)
Matthew R. Kumjian, CIMMS/Univ. of Oklahoma and NOAA/NSSL, Norman, OK ; and J. Snyder, A. V. Ryzhkov, D. S. Zrnic, S. Frasier, and H. B. Bluestein

Presentation PDF (2.7 MB)

Polarimetric radar observations provide remarkable insight into the microphysics of severe convective storms. Recent research on supercells utilizing polarimetric radars has revealed distinct and intriguing signatures regarding storm evolution and severity. Studies have investigated polarimetric data at S, C, and X bands independently, but so far none have compared observations of tornadic supercells at different radar wavelengths. Herein we investigate similarities and differences in the data from tornadic supercells at S band (from central Oklahoma), C band (from Enterprise, Alabama), and X band (from the Oklahoma panhandle). Though a direct comparison of the same storm is not yet available, the consistent appearance of certain features in supercells allows for a unique analysis of microphysics enhanced with the indirect comparisons of these multiwavelength polarimetric data.

Signatures observed at all three wavelengths include the tornadic debris signature, ZDR arc, and midlevel rings of enhanced ZDR and reduced ρHV. Important differences include the low-level hail signature (which may not appear at C band or X band). Also, data analysis at different wavelengths must account for varying degrees of attenuation and differential attenuation, which can create ambiguities in hydrometeor classification algorithms. This study raises important issues and considerations pertinent in comparing polarimetric data at different radar frequencies, which have implications for the upcoming VORTEX2 field campaign. One of the significant new components in the VORTEX2 program will be the extensive use of polarimetric data from S-, C-, and X-band radars.

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