Effects of PBL Mixing on Simulated NO2 Profile Shapes in the Coupled WRF/CMAQ Model and Comparison to Observations during DISCOVER-AQ July 2011

The first deployment of the NASA Earth Venture -1 DISCOVER-AQ (Deriving Information on Surface conditions from Column and Vertically Resolved Observations Relevant to Air Quality) project was conducted during July 2011 in the Baltimore-Washington region. The P-3B aircraft provided in situ vertical profiles of meteorological quantities, trace gases, and aerosols over six Maryland Department of the Environment (MDE) air quality monitoring sites over fourteen flight days. A major goal of DISCOVER-AQ is to better understand the processes, such as vertical mixing, controlling profile shape and linking column abundances to surface concentrations for NO2. Model vertical profiles are vital for obtaining accurate satellite retrievals of NO2 and thereby improving the applicability of satellite data for air quality analyses. Accurate simulatiions of the diurnal evolution of the NO2 profiles will be especially important for geostationary satellite retrievals. Model simulations performed using six commonly used PBL schemes with the coupled WRF/CMAQ model will be used to investigate the impact of vertical mixing on NO2 profile shapes. These modeled profiles will also be compared to the observed profiles to evaluate which PBL scheme (if any) best captures the in situ profiles, as well as PBL depth and the observed state of mixing. Lastly, the impact of PBL scheme on the column-surface relationship for NO2 will also be evaluated, and compared to observations.