Comparison of AERONET and SKYRAD4.2 inversion products retrieved from a Cimel CE318 sunphotometer

[摘要] SKYNET is an international research network of ground based sky – sunphotometersfor the observation and monitoring of columnar aerosolproperties. The algorithm developed by SKYNET is called SKYRAD.pack, and it is used on Prede instruments only. In this study, we havemodified the SKYRAD.pack software in order to adapt it to Cimelsunphotometers. A one month database of Cimel data obtained at Burjassot(Valencia, Spain) has been processed with this program and the obtainedinversion products have been compared with AERONET retrievals. In general,the differences found were consistent with the individual error assessmentsfor both algorithms. Although the aerosol optical depth compared well for anyaerosol burden situation (rmsd of 0.002–0.013 for all wavelengths),inversion products such as the single scattering albedo, refractive index andasymmetry parameter compared better for higher turbidity situations. Thecomparison performed for cases with an aerosol optical depth at440 nm over 0.2 showed rms differences of 0.025–0.049 for singlescattering albedo, 0.005–0.034 for the real part of refractive index,0.004–0.007 for the imaginary part of the refractive index and 0.006–0.009for the asymmetry parameter. With respect to the volume distributions,the comparison also showed a good agreement for high turbidity cases (mainlywithin the 0.01–7 μm interval) although the already knowndiscrepancy in the extremes of the distribution was still found in 40% ofthe cases, in spite of eliminating data and instrumental differences present inprevious studies.

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