posted on 7:32 PM, July 6, 2016
Project leader: Dr. Roland Stull
Currently, wildfire smoke dispersion modeling in BC is performed using the BlueSky Modelling Framework, run daily at UBC during the forest-fire season. This research project aims to improve the accuracy of smoke dispersion predictions by incorporating a new plume rise module into the BlueSky modeling system.
This project will develop a new set of equations to estimate plume rise. Preliminary large eddy simulations (LES) suggest that buoyancy at the fire front creates a boundary-layer- scale circulation that draws relatively clean near-surface air ahead of the flames towards the plume – in the direction opposite to ambient wind. The result is that PM2.5 is injected into a deep smoke layer within the top 2/3 of the boundary layer, while the bottom 1/3 behaves more like a line of traditional plume rise with clean air inflow from both sides of the fire line. Project researchers will use a large, varied set of LES runs to parameterize the plume growth above a simulated fire line.
By numerically experimenting with different wind speeds, boundary-layer depths, and fire intensities, project researchers will have sufficient information to produce analytical equations that scale properly to different size fires and environmental conditions. Ultimately, the BlueSky model enhanced with the new plume rise algorithm can be used operationally to provide air quality managers and decision-makers in British Columbia with more accurate smoke dispersion predictions.