Crown Fire Modeling and Its Effect on Atmospheric Characteristics

Abstract

The article is concerned with the experimental study of the crown fire effect on atmospheric transport processes: the formation of induced turbulence in the vicinity of the fire source and the transport of aerosol combustion products in the atmosphere surface layer at low altitudes. The studies were carried out in seminatural conditions on the reconstructed forest canopy. It was established that the structural characteristics of fluctuations of some atmosphere physical parameters in the case of a crown fire practically coincide with the obtained earlier values for a steppe fire. The highest concentration of aerosol combustion products was recorded at a height of 10–20 m from the ground surface. It was found that the largest number of aerosol particles formed during a crown fire had a particle diameter of 0.3 to 0.5 µm. As a result of experimental data extrapolation, it is concluded that an excess of aerosol concentration over the background value will be recorded at a distance of up to 2000 m for a given volume of burnt vegetation. It is of interest to further study these factors of the impact of wildfires on atmosphere under the conditions of a real large natural wildfire and determine the limiting distance of aerosol concentration excesses over background values.

Study of the influence of thermal impact from a ground fire on the ignition of a model forest canopy

“…The choice of spectral interval is determined by the emission spectrum of the main combustion products of the flame [10]. To correct flame emissivity and control wildfire front spread, racks with XA (chromel-alumel) type K thermocouples were placed inside the experimental line [9]. The experimental site (Figure 1) was an area of undergrowth and shrubs 1 and a forest canopy model 2.…”

“…On the basis of the IAO SB RAS, long-term studies of wildfires under various conditions, including natural ones, are carried out at the test site [8,9]. In the process of organizing and conducting such studies, considerable expertise and knowledge have been gained, and data on characteristics of wildfire fronts, their occurrence and spread, their influence on meteorological parameters, characteristics of turbulence in the atmosphere, emissions, and transfer of combustion products have been obtained.…”