Assessing the Impact of Aerosol-Cloud Interactions on NWP

The UK Met-Office have developed a new multi-moment 3-phase bulk microphysics scheme, which is coupled to aerosol for the Unified Model (UM). The scheme includes two way coupling between aerosol and cloud, meaning that both the impact of aerosols on clouds and clouds on aerosols can be examined. One of the main drivers for this development is to investigate whether the inclusion of aerosol in cloud microphysics improves skill of NWP, and if so what microphysical complexity is required. To assess this we have been using the UM in nested high resolution (< 1 km grid space ) Limited Area Model (LAM) mode to understand the role of aerosols in various cloud types, i.e. Marine Sc, trade wind cumulus, cold air outbreak and deep convection. In this work, we present results from sensitivity simulations of deep convection using the LAM set-up for TWP-ICE. The results are compared with published model intercomparison results and observations. The impact of changes in prognostic aerosol and aerosol processing on cloud morphology, radiative properties and precipitation will be investigated.