A Discussion on recent research in air pollution - The application of a pulsed-light rangefinder (lidar) to the study of chimney plumes

Abstract

Lidar observations, depending on the detection of backscatter from a pulse of light by particles along its path, have been used to study chimney plumes and their environment. Important technical improvements to the basic equipment have included the use of swept gain and the development of a brightness modulated display. A number of examples of lidar scans through plumes are presented to demonstrate the value of the improved display. Lidar observations of plumes over periods of about an hour have been used to predict the concentration of pollution at the ground. In neutral conditions, the predictions were significantly better than predictions based only on meteorological data. Observations of the rise and growth of a plume have suggested that, in the equation of motion describing the rise of a plume element, the rate of change of upward momentum should be equated to about one-half rather than the whole of the buoyancy force. Finally, a technique of analysis leading to vertical profiles of aerosol concentration in the lower layers of the atmosphere is outlined. These profiles often reveal features that are vital to a full understanding of plume behaviour.

Techniques for laser remote sensing of the environment

“…Mie scattering lidar exhibits high sensitivity in detecting smoke plumes and particulate emissions from smoke stacks, aircrafts and automobiles (Shimizu et al, 1980). The capability of the laser radar for observing the rise, diffusion and transport of plumes has proved helpful in verifying plume models useful for predicting environmental concentration levels (Hamilton, 1969). The SRI International Mark IX mobile system was used to trace smoke plumes at about 130 km downstream of the power plant, and the airborne system was capable of mapping smoke particle distribution over a wide area (Uthe et al, 1982 andUthe, 1983).…”

Scalable lidar technique for fire detection

“…The first lidar assisted analysis of emissions produced by power plants, factories, and forest fires was carried out in late 1960s 4,5 . Since that time, the interest in lidar has been steadily increasing, and lidar methods [6][7][8][9] , along with the algorithms for system optimization 10 and lidar signal processing [11][12][13][14][15][16] , are now widely used for atmosphere research and monitoring.…”