Study of the effect of a wildfire on the local characteristics of the atmosphere using remote sensing methods
E.L. Loboda1,2, I.A. Razenkov2, M.V. Agafontsev1,2, V.V. Reyno2
1National Research Tomsk State University, Tomsk, Russia
2V.E. Zuev Institute of Atmospheric Optics of Siberian Branch of the Russian Academy of Science, Tomsk, Russia
Keywords: wildfire, combustion, lidar, turbulence, aerosol
Abstract
This paper presents the results of an experiment on remote sensing of a smoke plume over a model fire with the use of a specialized lidar based on the backscatter enhancement effect and detecting optical turbulence. Burning was 1.600 m away, and the area of the model fire varied from 1, 9 and 25 m2. It was found that during combustion, the lidar recorded an increase in the echo signal in the main receiving channel, which registers aerosol scattering and the turbulent component, relative to an echo signal in the additional receiving channel, which registers only the aerosol. The width of the smoke plume did not exceed 20 m, an increase in the main echo signal was observed immediately after the plume in the distance range up to 300 m. In this experiment, a plume of warm smoke acted as a phase screen that changed the coherent structure of the laser beam. After the completion of intensive combustion, the temperature inside the plume rapidly decreased and the lidar recorded only the aerosol content. The appearance of two signs in the echo signal - an increase in the aerosol concentration and turbulence intensity - clearly indicates a source of burning. The lidar estimation of the values of the structural characteristic of the refractive index Cn2 at an altitude of 10 m above the combustion focus was compared with the data of the ultrasonic meteorological station AMK-03 at an altitude of 3 m and results of simulation of a grass-roots fire published earlier.
|
