Determination of Aerosol Size Distributions from Lidar Measurements

Abstract

It can be shown, theoretically, that the polarization properties of laser light scattered by a volume of air containing aerosols include considerable information as to the size distribution of the aerosols. A theoretical inversion model, utilizing the above information, is developed, which uses the Stokes parameters of the angularly scattered laser light as input data. These input data are generated theoretically from assumed size distribution functions of the aerosols. Both “perfect” measurements and measurements into which random errors are introduced are employed. These data are then used in the inversion model to generate predicted size distribution functions. Numerical experiments are performed with 0, 1 and 2% random error in the observations, in order to determine what accuracy is required in the lidar measurements. Comparisons between the actual and predicted functions are then made in order to assess the accuracy of the model.