A high-resolution FTIR spectrometer has been installed at Spitsbergen (79°N) in the German Arctic research station (Koldewey station) in order to measure atmospheric trace gases at high latitudes. For these ground-based absorption measurements either the sun or the moon are used as infrared light source depending on the time of the year. From the obtained spectra it is possible to retrieve the zenith total column densities of more than 20 trace gases in the troposphere and stratosphere. Furthermore, high-resolution spectra provide information on the vertical concentration profile. Seasonal variations of trace gas concentrations in the north polar atmosphere have been studied to get information about chemical and dynamical processes which could be responsible for stratospheric ozone depletion.