1.2
Numerical simulation of a wildfire event
Mary Ann Jenkins, York Univ., Toronto, ON, Canada
Clark et al (J. of Appl. Meteor., 1996; Int. J. Wildland Fire, 1996) demonstrate the feasibility of using a numerical atmospheric model coupled with a simple empirical fire model to investigate the energetics and some nonlinear processes associated with atmosphere-fire dynamics. These studies presented *short-fire line* simulations for *idealized* mean-flow conditions.
Using the most recently modified Clark et al coupled atmosphere-fire model, this study attempts to simulate a *real life* fire, Red Lake #7 Fire. Red Lake #7 is chosen as the first Clark et al case study because it demonstrated extreme fire behavior and had several classic features associated with large, intense, wind-driven wildfires. Red Lake #7 was first detected 21 May 1986, approximately 35 km northwest of the town of Red Lake (51 deg N, 83 deg W), and was finally brought under control 12 June 1986. It was large; final size 61,200 hectares. It spread both as a surface fire, with some intermittent torching, and as a continuously running and active crown fire, and reached average spread rates of 35 m/min while moving as a wind-driven active crown fire. Short range spotting was common, and allowed the fire to jump lines and lakes. And it generated it's own (local) severe weather. A towering convection column 13,000 metres above the fire produced a severe thunderstorm, causing numerous lightning fires downwind, while resulting precipitation ahead of the fire slowed the fire's progress dramatically. Outflow from the fire-generated thunderstorm was suspected to affect spread rate and behavior on the fire's flanks.
This case is an initial test of the most recent version of the Clark et al model, where a newly developed contact ignition parameterization allows the model to perform at larger resolutions than those used in Clark et al (1996a,b). This is a preliminary study, where model results of fire spread and fire spread rates under the variable synoptic-scale weather conditions will be presented and compared to those observed. Simulations of any or several of Red Lake #7's extreme fire features are done and will be presented.
Session 1, Coupled Fire - Atmospheric Models
Monday, 10 January 2000, 10:30 AM-2:00 PM
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