Examination of the impacts of ice nuclei aerosol particles on microphysics, precipitation and electrification in a 1.5D aerosol-cloud bin model

摘要

To study the impact of dust aerosol particles through their role as ice nuclei (IN) on the development of cloud microphysics and electrification, as well as on their contribution to the precipitation formation, we used a 1.5D detailed microphysics model to conduct sensitivity analysis of the Cooperative Convective Precipitation Experiment (CCOPE) case on 19 July 1981 in Miles City, Montana, USA. The simulated cloud microphysical properties demonstrate that the increase in IN concentrations enhances the number of ice particles produced by heterogeneous nucleation. As a result of increased ice particle formation, the enhanced ice growth via deposition in the Wegener-Bergeron-Findeisen mechanism, more extensive riming and thus an enhancement of ice aggregation, is primarily responsible for the increased numbers of large ice particles. The increased IN concentrations could result in earlier (similar to 6.5 minutes) and stronger (by a factor of 60) precipitation and greater raindrop mass due to enhanced ice phase process. The changes in microphysical processes resulting from increased IN concentrations lead to more large ice particles, which is primarily responsible for the enhanced charge separation process. Additionally, the charge density rises with the increased large ice particle concentrations and both of them reach their maxima at the same height.