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Status and Plans for the Next Generation Air Quality Modeling System Development
Citation:
Pleim, Jon, David-C Wong, R. Gilliam, J. Herwehe, R. Bullock, G. Pouliot, C. Hogrefe, D. Kang, Bill Hutzell, R. Mathur, S. Roselle, AND L. Ran. Status and Plans for the Next Generation Air Quality Modeling System Development. 2018 CMAS Conference, Chapel Hill, NC, October 22 - 24, 2018.
Impact/Purpose:
This presentation gives an overview of the EPA’s next generation air quality model development project. Progress to date is presented along with plans for the next steps.
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 atmospheric chemistry; 2. Regional (limited area) online meteorology and chemistry; 3. Offline (sequential) regional meteorology and chemistry. A one-dimensional air quality (AQ) component, built from state of the science chemistry and aerosol modules from the Community Multiscale Air Quality (CMAQ) model will be used in all three configurations. For the Global online configuration, the AQ component will be coupled to the Model for Prediction Across Scales – Atmosphere (MPAS-A), which is a global meteorological model with seamless mesh refinement developed at the National Center for Atmospheric Research (NCAR). The regional configurations will be coupled with WRF or a regional version of MPAS that has recently been developed at NCAR. In the presentation we will describe the coupled MPAS-CMAQ, which is an operational prototype of the Next Gen Model. We will describe the addition of physics schemes to MPAS that are particularly designed for air quality applications, as well as the addition of four dimensional data assimilation (FDDA). We will also show the latest tests of the MPAS-CMAQ model where we have incorporated CMAQ modules for atmospheric chemistry, deposition, cloud processes, and vertical diffusion into MPAS. In initial one month simulations (June 2013) MPAS-CMAQ shows good skill in simulating ozone in the populated areas of the world but tends to underpredicted ozone in high elevation areas. Longer simulations for the full year of 2016 show that Including ozone from the GFS analysis for all layers above the tropopause helps to reduce this underprediction.
