Storm duration analysis using TITAN

The Southeast Queensland (SEQ) region of Australia has been affected by drought conditions and critical water shortages in recent years. The Queensland Cloud Seeding Research Program (QCSRP) was conducted to assess the viability of using hygroscopic seeding to enhance precipitation in the SEQ region. An interesting result of the QCSRP and other past hygroscopic seeding experiments was that they observed a tendency for longer storm durations in seeded clouds. The objective of this study was to identify what factors are most strongly related to storm duration as a first step toward understanding how, aside from these factors, hygroscopic seeding may prolong storm duration. The factors that may influence storm duration were investigated using radar data collected during the QCSRP. The radar data were analyzed using the Thunderstorm Initiation, Tracking, Analyzing, and Nowcasting (TITAN) algorithm, which tracks storm cells and measures storm-specific properties such as duration, mean or maximum reflectivity, volume, and echo top height. Additionally, detailed analysis of the 39 randomized seeding cases from the QCSRP was conducted to ascertain what factors may influence storm duration. Each case was classified by storm evolution type (single pulse, multi-pulse, or complex) based on the number of pulses in maximum reflectivity height and the cell mergers or splits of the TITAN track. The case study analysis showed that the evolution types corresponded to distinct ranges of the population in relation to storm duration. It was also evident that cell mergers occurred in the longest-lasting storms in the case study analysis.