Comparisons of mesoscale model output with measurements are important for verifying and improving the models. Models are commonly compared with precipitation, temperature, and wind fields at the surface, and sometimes with vertical profiles from sondes or other sources. The behavior of the atmospheric boundary layer (BL) is key to modelling for air quality applications. Specifically, the BL height (mixing depth), wind speed in the BL, and temperature and water vapor profiles must be well-represented. We present comparisons between the NCEP Eta model and measurements made by lower-tropospheric wind profilers operating at 915 MHz. BL-top entrainment estimates from heat budgets are also compared. The profilers measure BL height, winds, virtual temperature, and turbulence intensity. Information about the presence and heights of clouds is also available from a laser ceilometer. The measurements
were made at the Flatland Atmospheric Observatory near Champaign/Urbana, Illinois.