On the Spectral Sensitivity of the Approximate Method for Retrieving Aerosol Size Distributions from Multispectral Solar Extinction Measurements

Abstract

Abstract This paper describes the retrieval of aerosol size distributions from the measurements of multispectral solar extinction data, by the use of two retrieval methods—a fast approximate method and the numerical nonlinear least-squares (NLLS) method. Comparison of eight sets of results obtained by the two methods, in general, show a good agreement to within 15%. In addition, size distribution results retrieved by the approximate method show that the method is particularly sensitive to the wavelengths used, and differences in the wavelengths used for making observations and for generating the look-up tables can lead to appreciable errors in retrieved results. Thus, one cannot assume a universal data base for use with radiometers with different wavelengths; generation of a separate data base for each set of wavelengths is recommended.