Total Ozone from Meteosat Second Generation

One of the new channels of the Meteosat Second generation (MSG) satellite is the 9.7 μm ozone absorption channel. The intention of this channel is to depict the dynamical structure in ozone layer i.e. the lower stratosphere, at high spatial and temporal resolution. This would complement the satellite observed tropospheric wind fields already used in numerical weather prediction. Figure ?? shows the weighting functions for the IR channels on SEVIRI a the standard tropical atmosphere, and nadir viewing geometry. This shows that weighting function of the IR 9.7 channel has an absolute maximum near the surface and a local maximum in the lowerpart of the stratosphere. To infer columnar ozone (Total Ozone, TOZ) from the SEVIRI observations a method originally prepared by Karcher for HIRS observations was modified to work with SEVIRI data. In the prelaunch period, a prototype version of this code was applied to GOES data and compared to total ozone derived from independent observations (e.g. TOMS and GEOS-DAS). This baseline operational retrieval method (hereafter refered to as GPTOZ)is a combined physical regression method. To compare the performance of this method with independent results, an optimal estimation method was adopted to work with geostationary satellite observations (hereafter refered to as GPTOE). This method was prepared by Engelen and Stephens to work with HIRS observations. Here we show some initial results of the application of the baseline operational and the optimal estimation method to SEVIRI images during the initial phases of commissioning. A full validation of the TOZ product is foreseen at a later stage. A first comparison to TOZ derived from HIRS observations and from TOMS is presented.