Climate change, water resources, and human activities are coherently interconnected. Increased temperature due to greenhouse gases likely exacerbates the severity, frequency, and duration of hydrological extremes, such as droughts, flooding, and convective storms. Moreover, atmospheric aerosols from various sources also regulate precipitation intensity and efficiency via interactions with convective clouds and large-scale circulations, while those effects have not yet been fully accounted for in the present climate models. The overachieving scientific objective of this project is to advance the process-level understanding of anthropogenic aerosol on precipitation extremes. A series of critical science questions will be addressed in the project: to what extent extreme precipitation is sensitive to cloud and aerosol physics in a new-generation global weather/climate model; whether local precipitation extremes are linked to local and remote aerosol variations; what type of aerosol effect exerts larger impacts on convective precipitation. Results from the project will provide scientific evidence for policymakers to frame effective actions to address the potential flooding and drought issues in the future climate. This five-year project plans to first improve the extreme precipitation simulation by enhancing the representations of aerosol and cloud microphysics in a fully compressible non-hydrostatic global climate model with regional refinement capability, Model for Prediction