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Impacts of Differences in Land Use Characterization and Dry Deposition Schemes on AQMEII4 CMAQ Simulations
Citation:
Hogrefe, C., J. Bash, Jon Pleim, D. Schwede, R. Gilliam, K. Foley, Keith Wyat Appel, AND R. Mathur. Impacts of Differences in Land Use Characterization and Dry Deposition Schemes on AQMEII4 CMAQ Simulations. 19th Annual CMAS Conference, NA (virtual meeting), North Carolina, October 26 - 30, 2020.
Impact/Purpose:
This abstract describes the analysis of CMAQ simulations performed by AESMD to contribute to the fourth phase of the Air Quality Model Evaluation International Initiative (AQMEII). The focus of the analysis is on investigating the impacts of differences in the representation of the underlying land use and the scientific formulation of the dry deposition process on simulated deposition fluxes and concentrations.
Description:
Phase 4 of the Air Quality Model Evaluation International Initiative (AQMEII) is focused on the diagnostic intercomparison and evaluation of dry and wet deposition of trace gases and aerosols simulated by regional-scale air quality modeling systems. Using the common emissions and boundary conditions datasets developed for AQMEII4, CMAQv5.3.1 simulations for the years 2010 and 2016 were performed over a North American modeling domain with both the M3DRY and STAGE dry deposition schemes. Meteorological fields for these simulations were prepared with WRFv4.1.1 using the Pleim-Xiu land-surface model and MODIS land-use classification scheme. CMAQ sensitivity simulations with both M3DRY and STAGE were performed for 2016 in which the WRFv4.1.1 Pleim-Xiu land-surface model was configured to use the NLCD40 land-use classification scheme and satellite-derived leaf area index (LAI) and vegetation fractions. Fields of surface characteristics, meteorological and concentration variables, dry deposition velocities, and deposition fluxes were analyzed to quantify the impacts of different land use characterizations and dry deposition schemes on simulated air quality and to gain mechanistic insights into model behavior. Results show that variability in the estimated dry deposition sink results from both differences in representation of the underlying land use and model process formulation and that the magnitude of both effects was comparable in the simulations analyzed in this study. CMAQ driven by the WRF configuration using MODIS yields consistently lower O3 and higher PM2.5 than the WRF configuration using NLCD40 and satellite-derived LAI and vegetation fractions. Using M3DRY results in lower PM2.5 year-round and generally lower O3 during the summer and higher O3 during winter compared to using STAGE for both 2010 and 2016. Land-use specific dry deposition velocities calculated by M3DRY and STAGE will be intercompared using diagnostic information about different surface resistance pathways generated as part of the AQMEII4 CMAQ simulations.
