The Community Multiscale Air Quality (CMAQ) model version 5.5 supports coupling with the Model for Prediction Across Scales (MPAS)

Last September the USEPA released a version of the Community Multiscale Air Quality (CMAQ) model that allows for coupling between the CMAQ model and NCAR’s Model for Prediction Across Scales – Atmosphere (MPAS-A). This novel framework enables seamless and consistent modeling of tropospheric chemistry and atmospheric physics from global to regional to local scales. Our poster depicts the coupling approach, air quality modeling performance, available configuration options, and features planned for future release.

Version 5.5 of CMAQ includes new modules that support coupling of CMAQ with either WRF or MPAS, and a new I/O module for reading and writing model inputs and outputs. We implemented meteorological data assimilation and tailored the surface and boundary layer physics of MPAS to improve the meteorological forcing for CMAQ. Experiments at several temporal and spatial scales show that the coupled system is skillful at simulating natural emissions, surface concentrations of ozone, and surface concentrations of fine particulate matter. This poster presents results from configurations that users can download from Amazon Web Services (AWS), including a global quasi-uniform 120 km mesh and a variable resolution mesh that refines from 92 km to 25 km cell spacing over North America.