SAOZ is UV-Visible (300-650 nm) diode array spectrometer developed at the Service d’Aéronomie in the late 80’s for monitoring stratospheric ozone after the discovery of the ozone hole by Farman et al. in 1985. It is a diode array flat field spectrometer of 1 nm resolution looking at sunlight scattered at zenith during twilight. The data analysed by Differential Optical Absorption Spectrometry allow the retrieval of daily ozone and NO2 total columns at sunrise and sunset, as well as total water vapour and oxygen dimmer and the detection of Polar Stratospheric Clouds (PSC) and volcanic aerosols.

The ozone measurement for the first time in the visible Chappuis bands between 450-600 nm, allows the continuous monitoring of the species throughout the year at the latitude of the polar circle, in all weather conditions.

First deployed in 1988 in both Dumont d’Urville in Antarctica (Pommereau and Goutail, 1988a) and Sodankyla in Finland (Pommereau and Goutail, 1988b), twenty SAOZ owned by CNRS and other institutes have been installed progressively since then at all latitudes including in the tropics. Alltogether their measurements are being used for monitoring every year the ozone destruction in the Arctic, for trend analysis and for the validation of a number of satellite O₃ and NO₂ column measurements (SBUV, TOMS, GOME, SCIAMACHY, OMI, GOME-2, IASI, OMPS-NPP, TROPOMI)

The SAOZ performances have been continuously evaluated during NDACC UV intercomparison campaigns in New-Zealand in 1992 (Hofmann et al., 1995), at Camborne in the UK in 1995 (Vaughan et al., 1996), Observatoire de Haute Provence in 1996 (Roscoe et al., 1999), Andoya in Norway in  2003 (Vandaele et al., 2005) and more recently in Cabauw (Netherland) in 2009 (Roscoe et al., 2010) and 2016 (Kreher et al., 2019 in preparation).