An in-depth comparison of plume calculations from the Quick Urban and Industrial Complex (QUIC) dispersion model to street- and roof-level concentration measurements for a daytime and night time release taken during the Joint Urban 2003 field experiment held in downtown Oklahoma City is presented. A number of improvements to the empirical-diagnostic wind solver to better account for high-rise buildings and dense urban areas will be discussed. Traditional plume statistical performance measures reveal that the code is performing as well as computational fluid dynamics models and meets the criteria proposed by Hanna and Chang (2012) for urban dispersion models. Statistics for the day and night release are fairly similar, and model performance drops slightly after the release is turned off in the flushing phase. Scatterplots indicate that rooftop measurements were generally well predicted, although the percentage of outliers (false negatives, large over predictions) was greater as compared to street-level measurements. Using all tracer data within a kilometre of the release, including rooftop samplers, from 39 to 46% of the model-computed concentrations were within a factor of two of the observations when broken up into four cases stratified by day or night and release on or off.
Keywords: urban dispersion, fast-response plume modelling, random walk dispersion modelling, flow around buildings, validation, Joint Urban 2003 tracer field experiment