Comparing the Aerosol Impacts on Deep Convective Updraft Characteristics in Two Cloud-Resolving Models

Comparisons between clean and polluted simulations among different cloud-resolving models (CRMs) provide useful information about both the variability and robustness of CRM representations of aerosol-cloud interactions. In this study, four simulations of isolated deep convection that occurred near Houston, Texas on 19-20 June 2013 were conducted under idealized clean and polluted aerosol conditions with two CRMs. Simulations were designed to use the same initialization datasets and model grids to eliminate these sources of uncertainty. Both models reproduced the meteorological event well based on radar observations and precipitation estimates. The impacts of increased aerosol particle concentrations on the deep convective clouds were compared between the models, and this presentation focuses on the frequency, size, and structure of the deep convective updrafts. Due to the isolated nature of the deep convective clouds for this event, deep convective updrafts were individually tracked in high-frequency model output, which provided large samples for comparisons between the simulations. The results presented here represent the preliminary findings of a planned multi-model comparison study, that will involve several additional CRMs, as outlined in the deep convective cloud roadmap of the Aerosol, Cloud, Precipitation, and Climate (ACPC) Initiative (www.acpcinitiative.org). Future work will include comparing simulated isolated cell properties with scanning polarimetric radar and lightning mapping array observations.