Webinar hosts: Joint Fire Science Program, International Association for Wildland Fire, and Widlfire Lessons Learned Center

Presenter: Yong Liu

Description: Plume height is one of the smoke properties that fire and air quality managers need to estimate in order to determine how much pollutants emitted from a prescribed burn are transported to remote populated areas from the burn site. Various models have been developed, but few have been systematically evaluated, making it difficult for mangers to understand the uncertainty of these tools. A JFSP project was conducted during 2008-2011 to evaluate and improve smoke plume rise models.

Twenty prescribed burns were measured in the Southeast with a ceilometer. A number of smoke plume rise models were evaluated and analyzed using the measured data together with regional air quality modeling. Improvements to smoke plume rise modeling were made by developing new schemes and models. The measured plumes had an average height of about 1 km. This value could be used as a first-order approximation, and a second-order approximation could be obtained by using the average for spring and fall seasons, and decreasing (increasing) by 0.2 km the average for winter (summer) season.

Simulations with Daysmoke were improved by incorporating a scheme for multiple plume updrafts. A regression model, developed using the measured smoke and RAWS data showed improved skill over some existing empirical models for the measured prescribed burn cases, suggesting that it may have the potential to be a practical tool for fire managers and air quality modelers to estimate plume rise of prescribed burning.