In winter 1992/93 we have performed ground-based FTIR measurements in the Arctic (79¿N, 12¿E) to derive column densities of stratospheric trace gases within the polar vortex. Due to the polar night the moon had to serve as infrared light source instead of the sun. It was possible to perform FTIR-measurements for about a week around full moon. Column densities of N2O, CH4, HF, HCl, O3, NO2, HNO3, and ClONO2 have been obtained. The spectra were recorded at 0.01 cm-1 or 0.02 cm-1 resolution using MCT or InSb detectors. Measurements with an aerosol lidar performed at the same site show that polar stratospheric clouds (PSCs) appeared several times during the polar night. It seems that the concentrations of the stratospheric trace gases are strongly influenced by the occurrence of PSCs. ¿ American Geophysical Union 1993