Spatiotemporal Variability of ZDR Column Altitudinal and Areal Extent in Tornadic and Nontornadic Supercells

Differential reflectivity (Z_DR) provides a means for enhanced understanding of the processes occurring throughout supercell thunderstorm life cycles by allowing for inference of microphysical distributions in these storms. Prior research has noted that Z_DR columns – areas of high values associated with strong updrafts that result from the lofting of liquid drops above the environmental 0˚C level – can be used as a proxy for updraft strength. Column altitudinal extent increases as an updraft intensifies, and results from a few studies show correlation between updraft broadness, evidenced by column areal extent, and updraft intensity. Assessing temporal and spatial patterns of these metrics may offer fundamental information concerning changes in updraft, and subsequently, mesocyclone strength. Additionally, these metrics can be influenced by environmental variability. Radar sample volume analysis of 115 supercells in tornadic and nontornadic environments spanning February 2012 – December 2014 will be discussed to emphasize variability of Z_DR column areal and altitudinal extent above the ambient 0˚C level. The degrees to which these metrics vary as a function of environment, supercell type (tornadic or nontornadic), and tornado intensity will be underscored. Predictive equations using multiple regression will also highlight the environmental parameters largely responsible for altitudinal and areal extent variability and allow for comparisons between subsets of the tornadic dataset.