STRATOSPHERIC TRACE GAS CONCENTRATIONS IN THE ARCTIC POLAR NIGHT DERIVED BY FTIR-SPECTROSCOPY WITH THE MOON AS IR LIGHT-SOURCE

In winter 1992/93 we have performed ground-based FTIR measurements in the Arctic (79-degrees-N, 12-degrees-E) to derive column densities of stratospheric trace gases within the polar vortex. Due to the polar ni ght 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 Cl ONO2 have been obtained. The spectra were recorded at 0.01 cm-1 or 0.0 2 cm-1 resolution using MCT or InSb detectors. Measurements with an ae rosol lidar performed at the same site show that polar stratospheric c louds (PSCs) appeared several times during the polar night. It seems t hat the concentrations of the stratospheric trace gases are strongly i nfluenced by the occurrence of PSCs.