Objective Identification and Tracking of ZDR columns in X-band Radar Observations of Storms

With the advent of rapidly scanning radar systems, it is imperative to automate the detection of features in radar images. We report on recent efforts to objectively identify Z_DR columns in X-band radar observations using the enhanced watershed algorithm (EWA; Lakshmanan et al. 2009), a method for identifying features in geospatial images. We discuss our choices for EWA parameters, such as threshold and hysteresis values. We apply the EWA to Z_DR observations obtained in convective storms during the 2016 and 2017 VORTEX-SE field campaign by the University of Massachusetts X-band, polarimetric, mobile Doppler radar (UMass X-Pol). During several intensive observing periods (IOPs), a variety of convective storm modes, including multicell clusters and quasi-linear convective systems, were observed, along with interactions between storms. Use of the EWA facilitates fast and objective tracking of the progression and behavior of each individual Z_DR column.