Dispersion modeling of a plume in the tar sands area

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  • The plume rise, spread and supporting meterological and source data given in Slawson et al (1978) were further analyzed in order to provide a more suitable data set upon which a site-tuned plume dispersion model could be developed. This dispersion model was considered to consist of a buoyant plume rise and growth phase followed by an atmospheric (Gaussian) dispersion phase. Since a truly predictive plume dispersion model is ultimately required for use in emission limitation control programs some effort was spent in developing and testing a predictive one dimensional planetary boundary layer model. Both analytical and simple numerical integration plume rise and growth models are described in some detail and tested against a reduced set of observed time-mean plume behavior. The numerical integration plume rise models (NIM) proved to be superior to the analytical models for the G.C.O.S. plume as: (1) non-linear temperature and win~ fields were more easily incorporated, (2) the Boussinesq approximation (which proved to be significant) was not required, and (3) low windspeed predictions were improved. Thus, a NIM is recommended for plume rise and growth in the buoyant phase. Considerable time was spent on re-analyzing the aircraft inplume transect data in an attempt to reduce scatter and obtain more consistent standard deviations of plume spread (sigmas) and their rates of growth under various atmospheric stability conditions so that a better comparison with several typing schemes could be made. Plume cross-section isopleths were constructed from the aircraft transect data for all cross-sections flown and are contained in an Appendix. The sigma data abstracted from the isopleths had less scatter than that found previously and correct trends in the data were noted. A sigma typing scheme due to Briggs (1975) was selected as best representative of that observed in the absence of cross-wind shear. Since an equivalent Gaussian plume dispersion model was required a tentative empirical formulation for the effects of cross-wind shear enhanced diffusion was extracted from the data. Also, a model that incorporates the effect of plume distortion directly into a modified Gaussian plume model is described and tested against some of the observed plume cross-sections. A plume rise and Gaussian dispersion model based on these measurements of the G.CO.S. plume is described and tested against observed ground plane aircraft transect data. This model may form the basis for a subsequent Syncrude plume model.

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    Conditions of Use Slawson, P.R., G.A. Davidson and C.S. Maddukuri, 1980. Dispersion modeling of a plume in the tar sands area. Syncrude Canada Ltd., Edmonton, Alberta. Environmental Research Report 1980-1. 316 pp. Permission for non-commercial use, publication or presentation of excerpts or figures is granted, provided appropriate attribution (as above) is cited. Commercial reproduction, in whole or in part, is not permitted without prior written consent. The use of these materials by the end user is done without any affiliation with or endorsement by Syncrude Canada Ltd. Reliance upon the end user's use of these materials is at the sole risk of the end user.