3D Trace gas concentration distributions from groundbased and airborne tomographic DOAS measurements

An overview on the AFO-2000 project "Tom-DOAS" is given. The project aims the assessment of concentration maps from DOAS measurements performed from ground or aircraft with more than ten light beams. 1) A first ground-based experiment was set up in April/May 2001 during the motorway campaign BABII (organised by Fiedler et al.): Two DOAS telescopes were directed onto eight retro reflector arrays mounted on two cranes, providing 16 light beams in total. From the data Luff and Lee profiles and the emission plumes of NO2 and ozone could be derived. 2) A new telescope type, the Multibeam telescope, was developed for the simultaneous measurement of multiple paths at ground. 3) An aircraft instrument was developed and about 20 flight hours of Tom-DOAS measurements were performed onboard a Partenavia aircraft in the Milano area (Italy) in the frame of the EU "FORMAT" project (July/August 2002) - in co-operation with the Institut für Umweltphysik of the University of Bremen 4) A new inversion software, "TOMOLAB", was developed, which converts the DOAS column data to concentration maps. It is used for the optimisation of tomographic setups using model data, e.g. for flight track choices, as well as for the inversion of real data sets from the measurements.