Star-pointing spectrometer for measurements of atmospheric ozone

Abstract

Optical measurement of the density of ozone and other atmospheric species at night is possible by using stars as light sources. The Technical Research Centre of Finland (VTT) has built a star-pointing spectrometer, which records stellar spectra by a two-dimensional CCD-array. The specirometer has a "slitless" design, so it can measure the absolute intensity level of a stellar spectrum attenuated by the atmosphere. A spectral inversion method designed for the satellite-based instrument GOMOS (Global Ozone Monitoring by Occultation of Stars) is applied for constituent retrieval from stellar spectra measured on ground. Analysis of simulated measurements shows that when averaging over one night the total ozone column can be measured by the VU spectrometer at an accuracy of 2 -3 %.