Research project MO/34/014 (Research action MO)
At Uccle, a long temporal series of total ozone is available based on Brewer spectrometer observations. It has recently been demonstrated that it is possible to derive aerosol optical depths (AOD) in the ultraviolet-B band (280-320 nm, referred to as UV-B) from these measurements (Cheymol and De Backer, 2003).
The aim of the proposed research is to further exploit this long temporal series of AODs estimated by this method. As we have 2 Brewer spectrophotometers at Uccle and this method has only been applied on the older of the two (#016), it will be applied on the other Brewer instrument (#178). Comparison of the data obtained from the different instruments at the same location will provide information on the accuracy of the AOD values. Trajectory analyses will be carried out to determine the origin of the aerosols. These analyses will help us to determine to what extent the amplitude of AOD variability is linked to dynamic conditions. In addition, as we have been members of an international network since 2001 (NDSC, Network for the Detection of Stratospheric Change), it will be possible to study the trends and climatology of AODs on a more extensive geographical scale by applying our method on other instruments at different locations. Added to these AODs in the UV-B, observations available at Uccle itself will be used to derive AOD values in the in the visible wave band. Thus, the extended AOD spectrum (from ~1000 nm to 306 nm) will provide the best possible characterisation of aerosols at Uccle.
