Aerosol optical depths measured with a Brewer spectrophotometer in the UV region and with a CIMEL Sun photometer in the visible and near infrared, both in operation at Ispra, Italy, are presented and analyzed. The analysis of the data acquired during 1 year includes a comparison of the spectral aerosol optical depth measured with the Brewer spectrophotometer at various wavelengths, as well as comparisons between the aerosol optical depth measured by the Brewer and the simultaneous measurements taken with the CIMEL Sun photometer. The strong correlation between the measurements of aerosol optical depth obtained from the two instruments demonstrates proper behavior of the instruments and of the methodologies used to retrieve the data. The variability of global UV-B and UV-A and total solar irradiance is investigated in relation to simultaneous spectral aerosol optical depth measured by the Brewer spectrophotometer and the CIMEL Sun photometer. The effect of the total ozone column on the correlation between the global UV-B data and the aerosols is analyzed. ¿ 2000 American Geophysical Union