Retrieval and characterization of ozone profiles from solar infrared spectra at the Jungfraujoch -: art. no. 4788

[1] Vertical distributions of ozone from June 1996 to November 2000 have been retrieved from high-resolution Fourier transform infrared (FTIR) solar absorption spectra recorded at the primary Network for Detection of Stratospheric Change station of the Jungfraujoch in the Swiss Alps (46.5degreesN, 8degreesE, 3580 m above sea level (asl). The retrievals were performed using the Optimal Estimation Method (OEM), both in a narrow spectral interval (1002.567-1003.2 cm(-1)) and in a broad spectral interval (1000.0-1005.0 cm(-1)) in the O-3 9.6-mum band. A thorough characterization of the retrievals has been performed following the lines of OEM, including an information content analysis, a study of the correlations between retrieved instrumental parameters and retrieved ozone concentrations, and an evaluation of the O-3 profile error budget. It is demonstrated that the information content is significantly higher for spectra in the broad microwindow, resulting in higher vertical resolutions, on the order of 8 km, of the retrieved profiles extending up to 40 km, and less correlations between retrieved parameters. An independent statistical verification of the retrieval results and their characterization has been performed by comparison of the FTIR ozone profiles with independent measurements. These are the ozone profile measurements from balloon soundings at Payerne, from the microwave radiometer at Bern and the lidar at Observatoire de Haute-Provence (OHP), and the total column data from the Dobson spectrophotometer at Arosa. Applying the optimum retrieval procedure in the broad spectral interval, an excellent agreement has been found between the FTIR O-3 profile data and the correlative data. The largest offset of the FTIR data in comparison with the correlative data is found with respect to the lidar data in the 24- to 40-km layer, and is on the order of 5%. No systematic biases have been found in the troposphere, neither in the upper troposphere-lower stratosphere (UTLS) up to 18 km. The dispersion of the relative differences between the data sets, if any, is never larger than half of the natural ozone variability.