Evaluation of urban surface parameterizations using measurements during the Texas Air Quality 2006 field campaign

The impact of urban land surface parameterizations in the WRF (Weather Research and Forecasting) model on the simulation of local meteorological fields is investigated to reduce meteorological biases in air quality model simulations over Texas region. A Noah land surface model (LSM), a modified LSM, and a single-layer urban canopy model (UCM) have been compared. For the model run, urban land use patches are renewed by the National Land Cover Data 2001. The model simulations were performed for 6 days from 12 August to 17 August during the Texas Air-Quality Study 2006 field experiment. Analysis was focused on the Houston-Galveston area. The model simulated temperature, wind, and boundary layer height were compared with observations from surface stations (CAMS), wind profiler, NOAA Twin Otter aircraft, and Ron Brown research vessel. The UCM simulation shows better results in the comparison of atmospheric boundary height and surface temperature than LSM simulations. The default LSM overestimates surface temperature and atmospheric boundary layer height significantly in urban areas due to suppression of latent heat flux in turbulent heat flux partitioning. The YSU atmospheric boundary layer scheme used in this study showed the discrepancy in the reproduction of atmospheric boundary layer height over water bodies. The reason for the discrepancy will be discussed.