Investigating the long-term evolution of subtropical ozone profiles applying ground-based FTIR spectrometry [Discussion paper]

This study investigates the long-term evolution of subtropical ozone profile time series (1999–2010) obtained from ground-based FTIR (Fourier Transform InfraRed) spectrometry at the Izaña Observatory ozone super-site. Different ozone retrieval strategies are examined, analysing the influence of an additional temperature retrieval and different constraints. The theoretical assessment reveals that the FTIR system is able to resolve four independent ozone layers with a precision of better than 6% in the troposphere and of better than 3% in the lower, middle and upper stratosphere. This total error includes the smoothing error, which dominates the random error budget.The research leading to these results has received funding from the European Community’s Seventh Framework Program ([FP7/2007- 2013]) under grant agreement no. 284421 (see Article II. 30. of the Grant Agreement). M. Schneider is supported by the European Research Council under the European Community’s Seventh Framework Program (FP7/2007-2013)/ERC Grant agreement no. 256961 and E. Sepúlveda enjoys a pre-doctoral fellowship from the Spanish Ministry of Education