The Anatomy and Physics of ZDR Columns: Investigating a Polarimetric Radar Signature with a Spectral Bin Microphysical Model

• DOI: 10.1175/jamc-d-13-0354.1
• Publication Date: 2014-04-21T20:12:54Z
• Authors: Matthew R. Kumjian; Alexander P. Khain; Nir Benmoshe; Eyal Ilotoviz; Alexander V. Ryzhkov; Vaughan T. J. Phi...
• Keywords: Supercooling; Graupel; Convective storm detection; Squall line

Abstract Polarimetric radar observations of deep convective storms frequently reveal columnar enhancements differential reflectivity Z DR . Such “ columns” can extend upward more than 3 km above the environmental 0°C level, indicative supercooled liquid drops being lofted by updraft. Previous observational and modeling studies columns are reviewed. To address remaining questions, Hebrew University Cloud Model, an advanced spectral bin microphysical model, is coupled with a polarimetric operator to simulate formation life cycle in continental storm. In doing so, mechanisms which produced clarified, including large raindrops updraft recirculation smaller formed aloft back into at low levels. The internal hydrometeor structure quantified, revealing transition from freezing hail height column. early formation, through growth maturity, demise described, showing how falling out weakening or ascending bubble dominates factor H , causing death column leaving behind its “ghost” drops. addition, practical applications their evolution explored. correlated strength, increases mass content ground after lag 10–15 min.