|Title||Determination of ultraviolet cosine-corrected irradiances and aerosol optical thickness by combined measurements with a Brewer spectrophotometer and a multifilter rotating shadowband radiometer|
|Publication Type||Articolo su Rivista peer-reviewed|
|Year of Publication||2008|
|Authors||Di Sarra, Alcide, Fuà D., Cacciani M., Di lorio T., Disterhoft P., Meloni Daniela, Monteleone Francesco, Piacentino Salvatore, and Sferlazzo Damiano Massimo|
|Keywords||Aerosol optical depths, Aerosol optical thickness, Atmospheric aerosols, Atmospheric radiation, Beer-lambert laws, Beverages, Brewer spectrophotometers, Central mediterraneans, Global irradiances, Global radiations, Independent measurements, Meteorological instruments, Optical depths, Radiometers, radiometry, Rotating shadow-band radiometers, Rotation, Solar fluxes, solar radiation, Solar zenith angles, Spectral irradiances, Spectrophotometers, spectrophotometry, Ultraviolet spectrophotometers, UV irradiances|
Combined measurements of diffuse-to-global radiation ratio and global spectral irradiances in the UVare used to derive cosine-corrected UV irradiances and aerosol optical depth (AOD). The diffuse-to-global radiation ratio is used first in the cosine correction of the global irradiance, then to calculate absolutely calibrated direct irradiances. The Beer-Lambert law is applied to derive the UV AOD using independent measurements of the extraterrestrial solar flux. The AOD can be derived with an uncertainty of about 0.03 at 60° solar zenith angle. The method was applied to measurements obtained with two UV multifilter rotating shadowband radiometers (UV-MFRSRs) and a MK III Brewer spectrophotometer on the Island of Lampedusa in the Central Mediterranean during two periods of 2002 and 2004. The derived AOD at 318 and 332 nm was compared with UV AOD measured at 318, 320, and 368 nm with different techniques. The retrieved AOD, combining MFRSR and Brewer measurements, is in good agreement with the optical depth derived with the other methods. © 2008 Optical Society of America.
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