Fine scale sensitivity studies of meteorological and air quality simulations using CMAQ and urbanized WRFV3.2 for Houston area for TexAQS 2006

Our interest is in evaluating the viability and performance of meteorological and air quality simulations at relatively fine (1km) grid resolutions for advanced urban applications (such as for human exposure assessment). For this effort, we conduct sensitivity studies using the most current urbanized features in the Weather Research and Forecasting (WRF) (version 3.2) model to drive the Community Multi-scale Air Quality (CMAQ) (version 4.7.1) model. We explore and perform in-depth analyses of WRF simulations using its various science options, with a special focus on the available science options that supports the Building Effect Parameterization (BEP) and a new Building Energy Model (BEP+BEM) in WRF V3.2 (including incorporating various sources of model inputs for gridded building descriptions, such as from the National Urban Database and Access Portal Tools (NUDAPT). Further, we implement in WRF and CMAQ thin urban canopy layers (~ 1m-5m) within the roughness layer of tall buildings to make possible resolving near surface vertical gradients in boundary layer and pollution modeling heretofore not possible for deep urban canopy situations.

The analyses of the resultant 1 km CMAQ simulations based on these various WRF sensitivities will be presented. Preliminary results indicate notable difference in the spatial structure of meteorological parameters and energy fluxes between the 1 km simulations compared to the coarser set of simulations, and between different physics schemes in WRF. It is critically import to ascertain the realism of these spatial structures. Ongoing evaluation with the intent of verifying the fine scale 3-D spatial structure in both the meteorological and air quality simulation sets using in situ measurements from both surface and airborne platforms are currently being investigated and will be shown.