The complementary use of TITAN-derived radar and total lightning thunderstorm cells

Thunderstorm Identification, Tracking, Analysis, and Nowcasting (TITAN) has traditionally been used to identify, track and provide short-term forecasts for thunderstorms defined by contiguous regions that exceed user-defined thresholds for size and radar reflectivity. We now apply this methodology toward the identification of thunderstorms using their total (cloud plus cloud-to-ground) lightning characteristics. Flash Extent Density (FED) is used to represent total lightning from Vaisala's Lightning Detection and Ranging (LDAR II) VHF time-of-arrival network centered at Dallas/Ft. Worth International Airport. The FED employs a “branched segment” reconstruction of the cloud flashes using temporal and spatial constraints. This method helps to normalize the effect of decreasing VHF source detection efficiency with range because flash detection efficiency decreases at a much slower rate with increasing distance from the center of the LDAR II network. Correlation analysis demonstrates that cell identification using total lightning compliments radar-identified characteristics. Observations suggest that splitting cells can be identified in advance with the development of additional FED cores within a radar indicated thunderstorm. In addition, the interaction of lightning between discrete cells may be an antecedent for the merger of radar-indicated thunderstorms. Case studies of data collected in spring-summer 2005 will demonstrate these concepts.