COMPARISON OF LAKE-BREEZE MODEL SIMULATIONS WITH TRACER DATA

During the 1980s there were numerous occurrences of ozone exceedances of federal standards in the Lake Michigan area. An intensive field pro gram was undertaken in order to gain insight into the dispersion patte rns in the area. A field experiment, which included a tracer release, was conducted on 16 July 1991 and provided the data used to test the s kill of a meteorological and dispersion modeling system. Specifically, the Regional Atmospheric Modeling System (RAMS) provided meteorologic al input to a Lagrangian Particle Dispersion Model. The RAMS model was run at a variety of grid spacings and configurations, and the output was compared to observations for each simulation. It was found that a minimum Delta x of 4km and a 3D setup were needed to accurately simula te the meteorology of 16 July 1991. The dispersion model was then run for each meteorological simulation and compared to aircraft data. Agai n the 3D simulations produced the best correlations to tracer data. It was also found in the 2D simulations that the highest correlation to meteorological variables was derived from the finest-resolution meteor ological simulation. Finally, a commonly used Gaussian plume model, th e Industrial Source Complex Model, was run using the best RAMS produce d meteorology. It was clear from the results that this model is not ap plicable to this case day and, in fact, failed to produce a nonzero co rrelation to the aircraft data.