ANALYSIS OF SIGNALS BACKSCATTERED FROM LARGELY DISPERSED AEROSOL

The power of a signal reflected from a dispersed medium composed of la rge particles is studied using the small-angle diffusion approximation of radiative transfer theory. The angular dependence of the backscatt ering function characteristic of aerosols in clouds and atmospheric ha zes is taken into consideration. The illumination and observation cond itions typical of remote sensing and vision systems are discussed. The signal power is calculated analytically as a function of aerosol micr ostructure parameters. In particular, the experimental results of the laser sounding of a dispersed medium under the conditions of multiple scattering are shown to require a special treatment at a wide angular divergence of the transmitter or the receiver beam of a recording inst rument. In this case, the time-base sweep of a signal may describe dif ferent parameters of the medium, depending on the optical path propaga ted by the signal arriving at the receiver. The actual angular depende nce of the backscattering function of dispersed media is almost univer sally required to properly describe active systems of vision with wide -beam illumination sources. Simple formulas for estimating the contrib ution of the actual angular dependence of the backscattering function are derived in the limit of large optical paths.