The paper entitled “Sensitivity of aerosol retrieval to geometrical configuration of ground-based sun/sky radiometer observations” has been published in the Journal of Atmospheric Chemistry and Physics.
This paper presents a sensitivity study of aerosol retrievals to the geometrical configuration of the ground-based sky radiometer observations.
Specifically, this study is focused on principal plane and almucantar observations, since these geometries are employed in AERONET (AErosol RObotic NETwork).
The following effects have been analyzed with simulated data for both geometries: sensitivity of the retrieval to variability of the observed scattering angle range, uncertainties in the assumptions of the aerosol vertical distribution, surface reflectance, possible instrument pointing errors, and the effects of the finite field of view.
The results show that almucantar retrievals, in general, are more reliable than principal plane retrievals in presence of the analyzed error sources.
This fact partially can be explained by practical advantages of the almucantar geometry: the symmetry between its left and right branches that helps to eliminate some observational uncertainties and the constant value of optical mass during the measurements, that make almucantar observations nearly independent of the vertical variability of aerosol. Nevertheless, almucantar retrievals present instabilities at high sun elevations due to the reduction of the scattering angle range coverage, resulting in decrease of information content. It is in such conditions that principal plane retrievals show a better stability.
The full references is:
Torres, B., Dubovik, O., Toledano, C., Berjon, A., Cachorro, V. E., Lapyonok, T., Litvinov, P., and Goloub, P.: Sensitivity of aerosol retrieval to geometrical configuration of ground-based sun/sky radiometer observations, Atmos. Chem. Phys., 14, 847-875, doi:10.5194/acp-14-847-2014,
You can download the paper at: