The Atmospheric Release Advisory Capability (ARAC) is a centralized emergency response system used to assess the impact from atmospheric releases of hazardous materials. As part of an ongoing development program, new three-dimensional diagnostic windfield and Lagrangian particle dispersion models will soon replace ARAC’s current operational windfield and dispersion codes. A
prototype model performance evaluation system has been implemented to facilitate the study of the capabilities and performance of early development versions of these new models relative to ARAC’s
current operational codes. This system provides tools for both objective statistical analysis using
common performance measures and for more subjective visualization of the temporal and spatial relationships of model results relative to field measurements. Supporting this system is a database of processed field experiment data (source terms and meteorological and tracer measurements) from over 100 individual tracer releases.