Stratospheric Trace Gas Measurements in the Near-UV and Visible Spectral Range with the Sun as a Light Source Using a Fourier Transform Spectrometer

Abstract

Spectra of the atmosphere have been measured in the near-UV and visible spectral range for the first time with a Fourier transform spectrometer using direct and zenith scattered sunlight. The observations were performed in the Arctic at 79°N, 12°E in 1994. Spectra were recorded in the wavelength range 310 to 1100 nm up to a resolution of about 0.0008 nm. The use of the FT spectrometer allowed the study of atmospheric trace gas concentrations in the whole spectral region between 500 and 31,000 cm⁻¹ (0.3–20 μm) with one instrument by only changing the beamsplitters and choosing different detectors. At a spectral resolution of 1.2 nm, the atmospheric absorptions of O₃ around 505 nm and NO₂ at 448 nm were analyzed. Results are compared with observations performed in the infrared with the same instrument, with TOMS data and with ozone balloon data.