W. P. Arnott Presentation on 9/12/2018

Model For Irradiance To Use In Estimating Uncertainty Caused by Surface Albedo
(It's difficult to see common atmospheric aerosol when they are over bright surfaces)

1. Nasa world view example.

2. Aqua satellite path.

3.

Schematic of Satellite Observations

Image from https://directory.eoportal.org/web/eoportal/satellite-missions/t/tansat#cRLZG1251Herb.

4. One dimensional model for R including multiple scattering between the ground and the atmosphere. (2 stream model).

Summary of 1D model. Click images for larger version.

Slide 15

Slide 21

5. Possible Improvement: Work only with the diffuse component of radiation (Total = Diffuse + Direct, Direct = exp(-τ)).

6. An excellent paper on multiple scattering, Craig F. Bohren. Multiple scattering of light and some of its observable consequences. American Journal of Physics, 55(6):524--533, June 1987.

Possible approach for obtaining the sensitivity of AOD retrieval to surface albedo.

7. Single scattering approximation for the sensivity of aerosol optical depth retrieval to surface albedo. The model assumes an infinitesimally thin aerosol layer near Earth's surface so that layer optics are only of the aerosol, and don't include Rayleigh scattering or absorption by air. Aerosol layer optical depth is assumed to be much less than unity. Aerosol layer extinction is modeled with (1-AOD); aerosol layer forward scattering is SSA*AOD*(1+g)/2 and backscattering is SSA*AOD*(1-g)/2. SSA is single scatter albedo; AOD is aerosol optical depth; g is aerosol asymmetry parameter.

Sensitivity of Aerosol Retrieval to Surface Albedo: Click images for larger version