OMI/Aura UV product validation using NILU-UV ground-based measurements in Thessaloniki, Greece

For the detection of the seasonal characteristics of the satellite irradiances it was shown that the 380 nm wavelength can be safely studied. The standard deviation of the strict cloud free overpass-time comparisons of ±12% may form a dependable measure of the seasonality imposed by the satellite retrieval algorithm assumptions. Additionally, the aerosol load at 340 nm and the possible solar zenith angle (SZA) effect on the comparisons was considered. No marked aerosol dependence was found with the ratio of satellite-to-ground irradiances remaining 1.1 ± 1.3 for the all-sky comparisons and 1 ± 0.1 for the clear-sky comparisons, while the SZA effect becomes appreciable only for angles higher than 70° with ratios 1.1 ± 1.0 for all-skies and 1.0 ± 0.1 for the clear-sky cases below that threshold.