Since 1958, the University of Liège (Belgium) has been maintaining a laboratory at the Jungfraujoch International Scientific Station, in the Swiss Alps, at an altitude of 3580 m. Equipped with two high-performance Fou rier-transform spectrometers, this laboratory is devoted to the study of the solar spectrum in the visible and in the infrared, at very high resolution. Its first objective was to improve the knowledge of the chemical composition of the sun's outer layers, but since 1977 interest has moved progressively towards atmospheric research. The Jungfraujoch laboratory is now one of the primary stations of an international network to monitor the changes in the abundances of various constituents of the Earth's upper atmosphere.
"High-resolution solar and atmospheric spectroscopy from the Jungfraujoch high-altitude station," Optical Engineering 34(9), (1 September 1995). https://doi.org/10.1117/12.205676