Science Seminars

12/10/2010 – The retrievals of detailed aerosol from AERONET sun/sky-radiometers: Overview of inversion principles, products and advances.

Speaker: Oleg Dubovik (Laboratoire d’Optique Atmosphérique, Université de Lille 1, France)
Date: Friday, Dec 10, 2010
Time: 4:00 PM
Location: Duane D-142

Seminar Abstract:

The AERONET operational retrievals rely on the algorithm by Dubovik and King [2000]. This algorithm is based on the principles of optimized statistical estimations and derives detailed size distribution and spectral complex refractive index by fitting measurements of both direct and diffuse radiation. It also provides such radiative characteristics as aerosol spectral single scattering albedo and phase functions. At the same time, the utilization of this retrieval over the years resulted in a number of the algorithm modifications. The modifications were driven by the desires to improve the retrieval accuracy and to provide user requested additional retrieval products. For example, forward modeling was updated by refining the assumptions on aerosol particle shape, modeling of surface reflectance, accounting for polarization effects. Such new products were developed as: fraction of non-spherical particles, estimates of broad band-radiative fluxes and aerosol forcing, extinction-to-backscatter and depolarization lidar ratios, error bars for each retrieved parameter, etc. Unfortunately, some of the newest inversion developments are not yet fully explained in the publications and may remain unclear for the users. The purpose of this presentation is to provide a synopsis of the retrieval algorithm principles, outline the important modifications in the AERONET retrieval and their rational, as well as, to overview all available and incoming retrieval products and their value.