Effects of smoothing and measurement-wavelength range on the accuracy of analytic eigenfunction inversions.

A smoothing technique is applied to improve the accuracy of inversions of Mie-extinction measurements with analytic eigenfunction theory. It is shown that a moderate amount of smoothing allows the inclusion of further terms, and thus extra information, in the expansion. The effects of measurement-wavelength range on the accuracy of inversions are also investigated, and it is shown that when large particles are present, measurements in the infrared region are necessary for accurate inversions.

Experimental validation of the solar aureole technique for determining aerosol size distributions.

This paper describes the inversion procedures by including multiple scattering contributions to almucantar radiance in the solar aureole region and discusses the retrieved size distribution results by comparing them with ground truth measurements. The agreement between the two sets of results is good and provides yet another experimental validation to show that the solar aureole technique is a simple, practical, and accurate method for obtaining the columnar size distribution of atmospheric aerosols. Comparisons between the results obtained by the two approximations--single and multiple scattering--show that the size distribution retrievals obtained by the latter are more accurate than those obtained by the former. Retrieved estimates of surface albedo show that even though surface albedo cannot be accurately determined from solar aureole measurements, these measurements can provide reasonable estimates. A recommendation is made for the use of solar aureole measurements from satellites to retrieve the size distribution and concentration of stratospheric and upper tropospheric aerosols.