High-resolution polarimetric radar observations of snow-generating cells

Matthew R. Kumjian, Steven A. Rutledge, Roy M. Rasmussen, Patrick C. Kennedy, Mike Dixon

Research output: Contribution to journalArticle

49 Scopus citations

Abstract

High-resolution X-band polarimetric radar data were collected in 19 snowstorms over northern Colorado in early 2013 as part of the Front Range Orographic Storms (FROST) project. In each case, small, vertically erect convective turrets were observed near the echo top. These "generating cells" are similar to those reported in the literature and are characterized by ≈1-km horizontal and vertical dimensions, vertical velocities of 1-2ms-1, and lifetimes of at least 10min. In some cases, these generating cells are enshrouded by enhanced differential reflectivity ZDR, indicating a "shroud" of pristine crystals enveloping the larger, more isotropic particles. The anticorrelation of radar reflectivity factor at horizontal polarization ZH and ZDR suggests ongoing aggregation or riming of particles in the core of generating cells. For cases inwhich radiosonde datawere collected, potential instability was found within the layer in which generating cells were observed. The persistence of these layers suggests that radiative effects are important, perhaps by some combination of cloud-top cooling and release of latent enthalpy through depositional and riming growth of particles within the cloud. The implications for the ubiquity of generating cells and their role as a mechanism for ice crystal initiation and growth are discussed.

Original languageEnglish (US)
Pages (from-to)1636-1658
Number of pages23
JournalJournal of Applied Meteorology and Climatology
Volume53
Issue number6
DOIs
StatePublished - 2014

All Science Journal Classification (ASJC) codes

  • Atmospheric Science

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