Coupling Rabbit Rules with Daysmoke for simulating fire spread and plume rise for an RxCadre aerial ignition prescribed burn

We coupled Rabbit Rules with Daysmoke to simulate fire spread, fire emissions, and smoke plume rise and dispersion for an aerial ignition prescribed burn conducted at Eglin AFB on 6 February 2011 as part of the RxCadre project. We used GPS coordinates of the helicopter as it dropped 6000 ignition balls on block 703C (1650 Acres) to initialize Rabbit Rules. Fuel types were determined via a color identification scheme applied to a Google Earth image of the burn area. Two fuel types were identified: grass only, and a mixture of pine needles and grass. Herbaceous fuels were not considered.

Rabbit Rules generated concentrations of hotter plume air during the course of the burn. These areas were expressed as pressure anomalies defining roots of the smoke plume or smoke updraft cores. Typically there were 3-4 pressure anomaly centers. A photo-image of the burn showed three distinct plumes.

Daysmoke was run with a three-core updraft plume initialized by a 10-min emissions model based on Rabbit Rules emissions. Daysmoke reproduced the observed plume – a three-core vertical tower that mushroomed at the mixing height. Because smoke was transported into the free atmosphere above the mixing layer, ground-level smoke concentrations were minimal. Daysmoke plume heights compared well with plume heights observed by ceilometer.