P67 Progress on implementing additional physics schemes into MPAS-A v5.0 for next generation air quality modeling

Herwehe, Jerold A., Robert C. Gilliam, O. Russell Bullock Jr., Jonathan E. Pleim, and Hosein Foroutan, U.S. Environmental Protection Agency

The U.S. Environmental Protection Agency (USEPA) has a team of scientists developing a next generation air quality modeling system employing the Model for Prediction Across Scales – Atmosphere (MPAS-A) as its meteorological foundation. Several preferred physics schemes and options available in the Weather Research and Forecasting (WRF) model are regularly used by the USEPA with the Community Multiscale Air Quality (CMAQ) model to conduct retrospective air quality simulations. These include the Pleim surface layer, the Pleim-Xiu (PX) land surface model with fractional land use for a 40-class National Land Cover Database (NLCD40), the Asymmetric Convective Model 2 (ACM2) planetary boundary layer scheme, the Kain-Fritsch (KF) convective parameterization with subgrid-scale cloud feedback to the radiation schemes and a scale-aware convective time scale, and analysis nudging four-dimensional data assimilation (FDDA). All of these physics modules and options have already been implemented by the USEPA into MPAS-A v4.0, tested, and evaluated (please see the presentations of R. Gilliam and R. Bullock at this workshop). Since the release of MPAS v5.0 in January 2017, work has been under way to implement these preferred physics options into the MPAS-A v5.0 code. Test simulations of a summer month are being conducted on a global variable resolution mesh with the higher resolution cells centered over the contiguous United States. Driving fields for the FDDA and soil nudging are provided by NOAA/NCEP's GDAS/FNL, GFS, and RUC analyses. Results from the MPAS-A v5.0 simulations utilizing these added physics schemes are evaluated against observations available from NCEP's Meteorological Assimilation Data Ingest System (MADIS).