Laura D. Fowler1, Mary C. Barth1,2, Michael Duda1, and Duseong Jo2

1 MMM/NCAR, 2 ACOM/NCAR

We implemented a novel initialization of aerosols using CAM-chem simulation outputs for use as “water-friendly” and “ice-friendly” aerosols in the aerosol-aware option of the Thompson cloud microphysics scheme in the Model for Prediction Across Scales (MPAS). Water-friendly aerosols are comprised of organic carbon, sulfates, and sea-salts whereas ice-friendly aerosols are composed of dusts. Using a python-based emissions tool developed for unstructured grid meshes, anthropogenic surface emissions of organic carbon and sulfate aerosols are provided from the monthly-mean CAMS inventory. For natural emissions, the GOCART chemistry sea-salt and dust emission schemes are utilized.

In addition to a physically based representation of surface emissions of aerosols for use with the aerosol-aware Thompson cloud microphysics scheme, we included the convective transport of aerosols and passive tracers in the scale-aware Grell-Freitas convection scheme. Convective transport includes wet scavenging and evaporation of aerosols in updrafts and downdrafts. We hypothesize that including the convective transport of aerosols will improve the vertical profiles of the number concentrations of the cloud liquid water and ice content in convective clouds leading to improved precipitation compared to those without convective transport at hydrostatic scales.

We present early results of the impact of our simple aerosol model on cloud microphysics and convection using the 15 km quasi-uniform resolution mesh. Our research outlines the need to build links between physics and chemistry to improve aerosols-clouds interactions in MPAS, not only initially at hydrostatic scales, but more importantly later at non-hydrostatic scales using variable-resolution meshes.