Modeling smoke plume patterns in drainage flows

Abstract

A three-dimensional diagnostic wind model for use in complex terrain has been combined with a three-dimensional trajectory and puff air quality model. The wind model utilizes a terrain following coordinate system and conserves both mass and momentum. The wind model provides the winds required by the predictive trajectory and puff dispersion model. Both the wind model and the dispersion models were compared with more complicated models and with wind and tracer gas data from the 1980 ASCOT experiment. Comparison of the wind model with Yamada's three-dimensional primitive equation solution showed that the diagnostic model gave essentially the same results. Both model's results compared well with the data. The trajectory and puff model was compared to both ADPIC model results and the SF6 tracer experiment results. Calculated concentrations were within 30 percent of those measured. These results suggest that the trajectory calculation is the major factor in dispersion over complex terrain. A smoke plume from a prescribed fire at midslope (Ford Flats) was simulated. The Putah Creek plume stayed in the drainage flow while the Anderson Creek and Ford Flats plumes were elevated and transported over the top of the Putah Creek plume.

Citation

Fosberg, M.A. 1985. Modeling smoke plume patterns in drainage flows. In: Proceedings, eighth conference on fire and forest meteorology. Washington, DC: Society of American Foresters: 153-158.