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The Advanced Air Quality Modeling System: The Global MPAS-CMAQ Model
Citation:
Pleim, Jon, D. Wong, R. Gilliam, J. Willison, J. Herwehe, R. Bullock, G. Pouliot, C. Hogrefe, D. Kang, G. Sarwar, Bill Hutzell, H. Foroutan, R. Mathur, AND L. Ran. The Advanced Air Quality Modeling System: The Global MPAS-CMAQ Model. CMAS 2020 Conference, Chapel Hill, NC, October 26 - 30, 2020.
Impact/Purpose:
This presentation reports on the ongoing development of the Advanced Air Quality Modeling System. Improvements in air quality modeling will directly inform research efforts on the link between air quality and human/ecological health at very high spatial resolutions. These results and the model development are useful for an array of partners and the broader modeling community. Air quality modelers and researchers in the academic, governmental, and private sectors can all leverage the research developed here. The model developments that allow for global long-term simulations of past weather with accuracy are applicable to the broader meteorological modeling community that may be interested in simulating events other than those focused on air quality (e.g., climate or hydrology modeling). This work will show that EPA modelers have adapted a next generation meteorology model MPAS for retrospective modeling to drive the CMAQ model at global scales. The addition of global coverage and seamless scale interactions will enable treatment of long-range transport across intercontinental scales and more realistic inclusion of contributions of global stratospheric ozone to ground level concentrations and deposition which will improve our air quality modeling capability.
Description:
A next generation air quality modeling system is being developed at the U.S. EPA to enable modeling of air quality from global to regional to local scales. The system will have three configurations: 1. Global meteorology with seamless mesh refinement and online (coupled) atmospheric chemistry; 2. Regional (limited area) online meteorology and chemistry; and 3. Offline (sequential) regional meteorology and chemistry. We have developed a global online configuration which includes the Model for Prediction Across Scales – Atmosphere (MPAS-A), developed at the National Center for Atmospheric Research (NCAR), coupled with the latest version of the Community Multiscale Air Quality (CMAQv5.3) model developed at the U.S. EPA. In this presentation we will present the initial evaluation of air quality model simulations by the MPAS-CMAQ system for the full year of 2016 using a mesh with 92 km global resolution refining to 25 km over North America. Global emissions from EDGAR-HTAP are combined with the 2016 EPA National Emission Inventory for the US. Evaluation of meteorology simulated by the EPA-enhanced version of MPAS-A that includes the addition of four-dimensional data assimilation (FDDA), the ACM2 PBL model, and PX land surface model will be presented in another talk. This presentation will focus on global and US evaluations of concentrations and deposition of air quality constituents. Evaluation includes comparisons to gas and aerosol surface-based measurement networks in the US and other regions of the world. In addition, we compare to global satellite data such as MODIS AOD and OMI NO2. Our technique of assimilating ozone concentrations from GFS analyses for layers above the tropopause is evaluated through comparisons to the WOUDC global ozonesonde network.
