Air quality is primarily influenced by local sources, but on regional scales the impact of upwind sources can have a significant impact.  Models that can simulate regions of interest at fine scale while including continental and hemispheric impacts are needed to quantify the drivers of atmospheric composition.  The MUlti-Scale Infrastructure for Chemistry and Aerosols (MUSICA) is intended to become the next generation community infrastructure for research on atmospheric chemistry and aerosols, investigating local-scale phenomena in the global context. MUSICA, which is part of the System for Integrated Modeling of the Atmosphere (SIMA), is being developed collaboratively by the National Center for Atmospheric Research (NCAR) and university and government researchers, with the goal of serving the international research and applications communities. The capability of unifying various spatio-temporal scales, coupling to other Earth System components and process-level modularization will allow advances on topics ranging from fundamental research to air quality to climate and couplings between ecosystems. MUSICA is also envisioned to become a platform that addresses the needs of policy makers and stakeholders.

This presentation will give an overview of MUSICA and describe the opportunities for community participation and collaboration.  Simulations using a variable resolution grid of 14-km horizontal resolution over the contiguous United States, and 1-degree elsewhere, have been performed to analyze air quality in a variety of conditions across the U.S.  Regions with impacts from regional biogenic emissions and wildfires have been studied in particular.  Results from MUSICA simulations with other variable resolution grids, such as 7-km resolution over South Korea, will also be presented.  Additional capabilities for MUSICA currently being developed include nonhydrostatic grid scales, flexibility to use various chemical mechanisms, and a flexible framework for model evaluation with atmospheric chemistry observations.