Polarimetric Signatures in Supercell Thunderstorms

Data from polarimetric radars offer remarkable insight into the microphysics of convective storms. Numerous tornadic and nontornadic supercell thunderstorms have been observed by the research polarimetric Weather Surveillance Radar-1988 Doppler (WSR-88D) in Norman, Oklahoma (KOUN); additional storm...

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Bibliographic Details
Published in:	Journal of applied meteorology (1988) 2008-07, Vol.47 (7), p.1940-1961
Main Authors:	Kumjian, Matthew R., Ryzhkov, Alexander V.
Format:	Article
Language:	eng
Subjects:	Aircraft C band Cells Climatology Convective storms Doppler effect Doppler sonar Downdraft Earth, ocean, space Electronics Exact sciences and technology External geophysics Geographical locations Hail Hydrometeorology Meteorology Meteors Microphysics Polarimetric radar Polarimetry Precipitation Quantitative analysis Radar Radar signatures Raindrops Signatures Simulation Storm data Storms Storms, hurricanes, tornadoes, thunderstorms Studies Supercell thunderstorms Surveillance radar Thunderstorms Tornadoes Updraft Vertical air currents Weather Wind
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Summary:	Data from polarimetric radars offer remarkable insight into the microphysics of convective storms. Numerous tornadic and nontornadic supercell thunderstorms have been observed by the research polarimetric Weather Surveillance Radar-1988 Doppler (WSR-88D) in Norman, Oklahoma (KOUN); additional storm data come from the Enterprise Electronics Corporation “Sidpol” C-band polarimetric radar in Enterprise, Alabama, as well as the King City C-band polarimetric radar in Ontario, Canada. A number of distinctive polarimetric signatures are repeatedly found in each of these storms. The forward-flank down-draft (FFD) is characterized by a signature of hail observed as near-zeroZ DRand highZ HH. In addition, a shallow region of very highZ DRis found consistently on the southern edge of the FFD, called theZ DR“arc.” TheZ DRandK DPcolumns and midlevel “rings” of enhancedZ DRand depressedρ HVare usually observed in the vicinity of the main rotating updraft and in the rear-flank downdraft (RFD). Tornado touchdown is associated with a well-pronounced polarimetric debris signature. Similar polarimetric features in supercell thunderstorms have been reported in other studies. The data considered here are taken from both S- and C-band radars from different geographic locations and during different seasons. The consistent presence of these features may be indicative of fundamental processes intrinsic to supercell storms. Hypotheses on the origins, as well as microphysical and dynamical interpretations of these signatures, are presented. Implications about storm morphology for operational applications are suggested.
ISSN:	1558-8424 0894-8763 1558-8432 1520-0450