Intercomparison of aerosol optical depth measurements in the UVB using Brewer spectrophotometers and a Li-Cor spectrophotometer

The first Iberian UV radiation intercomparison was held at "El Arenosillo"- Huelva station of the Institute Nacional de Tecnica Aeroespatial (INTA) fr om September 1 to 10, 1999. During this campaign, seven Brewer spectrophoto meters and one Li-Cor spectrophotometers measured the total column aerosol optical depth (AOD) at 306, 310, 313.5, 316.75 and 320 nm. The BOD calibrat ion of one Brewers was transferred to all other Brewers using one day of in tensive measurements. The remaining days were used to observe the stability and reproducibility of the AOD measurements by the different instruments. All Brewer spectrophotometers agreed to within an AOD of 0.03 during the wh ole measurement campaign. The differences in AOD between the Li-Cor spectro photometer and the Brewer spectrophotometers were between -0.07 and +0.02 a t 313.5, 316.75, and 320 nm. This investigation demonstrates the possibilit y of using the existing worldwide Brewer network as a global UV aerosol net work for AOD monitoring.