This proposed study was in response to the Joint Fire Sciences FA-FON0016-0004 Fire and Smoke Model Evaluation Experiment (FASMEE) Task 5 - Modeling leads. The purpose was to evaluate Daysmoke and PB-Piedmont (PB-P) models to provide information for the FASMEE Phase 2 design. Daysmoke is a local smoke plume dispersion and transport model developed specially for prescribed burning (Rx). It is complementary to physically and chemically based regional smoke and air quality modeling tools and is able to provide some unique information such as the role of multiple updraft cores. PB-P is a very high resolution meteorological and smoke model designed for simulating near-ground smoke transport at night over complex terrain. The main objectives of this project were to conduct pre-burn simulations to provide information on model capacity, gaps and FASMEE measurement needs, and to conduct sensitivity experiment to understand the impacts of uncertainty in FASMEE experimental burns and measurements. The scientific issues for this project were the roles of multiple smoke sub-plumes in plume dynamics, smoke modeling sensitivity to uncertainty in burn conditions and model parameters, and the processes and mechanisms for formation of night smoke drainage and fog. Simulations have been conducted for historical Rx burns to evaluate Daysmoke and PB-P model performance, for hypothetical burns at FASMEE measurement sites to understand uncertainty of smoke plume development and modeling, and for idealized fire line burns to compare performance among fire and smoke models with varied physics and complexity.

The simulations and experiments indicate that Daysmoke is able to estimate plume rise of Rx burns with reasonable accuracy. Smoke behaviors dramatically change with weather patterns. Plume rise decreases remarkably with increasing number of smoke multiple cores. Plume rise simulation is very sensitive to setup of “burner” method. Night-time smoke drainage and super-fog occurred often with Rx burns. These findings suggest that the comprehensive FASMEE measurements of the related properties would be a key for improving Daysmoke and PB-P performance. The FASMEE burns should be conducted under such conditions so that the field measurements would collect simultaneous data of these properties for understanding the multiple sub-plume dynamics and evaluating and advancing the modeling tools. Weather conditions on the FASMEE experimental burn days are critical for obtaining anticipated smoke plumes for field measurements and could vary on daily basis at Ft Stewart. In addition, it is highly recommended to conduct night-time smoke measurements during FASMEE experiment in both the southeastern and the southwestern burn sites.

This project contributed to the development of the FASMEE Study Plan by providing information on model capacity, gaps, the data needs for model improvements, and desired burn and smoke conditions, and by drafting a few subsections in the Appendixes and main body. The major deliverables from this project include pre-burn modeling results, and presentation and manuscript on FASMEE modeling activity.