4 January 1995 Errors in UV reflectivity and albedo calculations due to neglecting polarization
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Abstract
Ultraviolet (UV) spectrometer of the atmosphere is becoming increasingly important for the determination of ozone concentrations from space (cf., e.g., the new satellite instruments GOME on board ERS-2 and SCIAMACHY on board Envisat-1). By measuring the shape of the ozone Huggins bands, which are situated from about 310 to 340 nm, accurate ozone column and profile detection is possible in principle. In the retrieval procedure, based on radiative transfer calculations of atmospheric UV reflectivity, polarization is usually neglected. However, this may introduce an appreciable error, because in the UV molecular (Rayleigh) scattering, which can yield a high degree of polarization, is the dominant scattering process. In this study the magnitude and spectral dependency of the reflectivity error in the Huggins bands due to neglecting polarization has been investigated. The maximum relative error in the nadir reflectivity is of the order of 5%. Furthermore, the error shows the structure of the Huggins bands, amounting to about 1% in the relative reflectivity. This has implications for the retrieval of ozone column and profile. The UV albedo has been found to be in error by at most about 2% when polarization is neglected. This is contrary to the usual assumption that angularly integrated quantities are not influenced by neglection of polarization in molecular scattering atmospheres.
© (1995) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Piet Stammes, Piet Stammes, } "Errors in UV reflectivity and albedo calculations due to neglecting polarization", Proc. SPIE 2311, Atmospheric Sensing and Modelling, (4 January 1995); doi: 10.1117/12.198580; https://doi.org/10.1117/12.198580
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