Microphysical and dynamic evolution of convection observed by polarimetric radar under the influence of cloud seeding

Abstract

The microphysical and dynamic evolution characteristics of two convections (labeled A and B) were analyzed using polarimetric radars during the same weather conditions under the influence of ground-based rockets and artilleries containing silver iodide (AgI). The ice and liquid water content (IWC and LWC, respectively), hydrometeor classification and three-dimensional wind structure were retrieved to analyze the convection evolution. The results indicate that the convective evolution trends after AgI seeding are related to the preoperation dynamic and microphysical structure. The ice processes of convection A are more active before operation, with a high echo center of gravity, larger IWC and LWC, and a predominance of graupel above the freezing level. The center of gravity of the convection gradually decreases, and the cloud collapses and gradually dissipates during AgI seeding. Convection B has more active liquid processes, with a stronger updraft but lower IWC and LWC. During AgI seeding, ice processes of the convection have a tendency to be enhanced, with a higher echo center of gravity and increases in IWC, and LWC below the freezing level. During significant wind shear, the path of convection may tend to align with the background guided flow at different levels, depending on the different intensities of convection influenced by AgI seeding. The convection intensity and its matching with vertical wind shear should be considered when artificially seeding convection.