The Impact of Aerosol Prediction in Cloud-Scale Numerical Prediction Models (Invited)

With increasing computational power, models that explicitly predict the concentrations and properties of aerosols that can serve as cloud condensation nuclei and/or ice nucleii are moving closer to being run operationally. Similarly, numerical weather prediction (NWP) models are now at the point where it is common to have operational domains run at near cloud-scale resolutions, with horizontal grid-spacings of 1-4 km. With this type of configuration, nearly all clouds and precipitation processes are represented by bulk microphysics parameterization schemes. In the foreseeable future, aerosol-prediction models will be fully coupled with operational NWP models.

At Environment Canada, research is currently underway to investigate the impact of the chemistry-dynamics interaction to NWP through a fully coupled model (GEM-MACH) with a 2.5-km grid spacing. The NWP model uses a detailed two-moment bulk microphysics scheme, which provides the link between the chemistry and meteorology of the modeling system. Results will be presented from the GEM-MACH/GEM modeling system. Emphasis will be given on providing a detailed overview on how predictive aerosols affect NWP through the various processes that depend, directly and indirectly, on the aerosol input into the microphysics scheme.