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The atmospheric abundance of several radiatively and chemically active trace gases is changing. In order to understand the proper atmospheric processes as transport of trace gases and chemical reactions it is necessary to perform simultaneous and global observations of these trace constituents. This can be achieved with Fourier Transform Spectrometers (FTS) detecting wide spectral i ntervals i n the mid-Infrared (IR). During the last ten years several FTIR experiments for measuring trace species have already been carried out by different scientific groups (overview see Fischer 1992). In the following only more recent measurements of FTIR-instruments will be treated . There exist u ncooled mid-IR experiments wh ich yielded still very i nteresti ng scientific results even if they provide only sun occultation measurements, i.e. these measurements are restricted to a limited number of occasions during dawn and dusk. A widely known FTIR experiment of such type is the so-called ATMOS (Atmospheric Trace Molecule Spectroscopy) Project. During several Spacelab flights a large number of sun occultation measurements have been recorded and to a far degree already analysed. The results are concentration profiles of about 30 trace gases in both the Northern and Southern hemisphere. Cooled FTIR instruments have already been operated aboard stratospheric balloon gondolas by some scientific groups and aboard a Transall aircraft. The recorded emission spectra are of high quality and allow the determination of vertical profiles/column amounts of many trace species, e.g. of the main reactive and reservoir nitrogen compounds. For example, the MIPAS (Michelson Interferometer for Passive Atmospheric Sounding) experiments provided remarkable results with respect to ozone research in the Arctic, e.g. the spatial and time-dependent distribution of the important reservoir species CIONO2. The talk will give an overview on FuR instruments in operation, a selection of the more recent measurements and the corresponding scientific results. Keywords: Remote sensing, trace species, Fourier Transform Spectrometers, midInfrared
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