Ozone ProfilE Retrieval Algorithm (OPERA) for nadir-looking satellite instruments in the UV–VIS

Abstract

Abstract. For the retrieval of the vertical distribution of ozone in the atmosphere the Ozone ProfilE Retrieval Algorithm (OPERA) has been further developed. The new version (1.26) of OPERA is capable of retrieving ozone profiles from UV-VIS observations of most nadir-looking satellite instruments like GOME, SCIAMACHY, OMI and GOME-2. The setup of OPERA is described and results are presented for GOME and GOME-2 observations. The retrieved ozone profiles are globally compared to ozone sondes for the years 1997 and 2008. Relative differences between GOME/GOME-2 and ozone sondes are within the limits as specified by the user requirements from the Climate Change Initiative (CCI) programme of ESA (20 % in the troposphere, 15 % in the stratosphere). To demonstrate the performance of the algorithm under extreme circumstances, the 2009 Antarctic ozone hole season was investigated in more detail using GOME-2 ozone profiles and lidar data, which showed an unusual persistence of the vortex over the Río Gallegos observing station (51 • S, 69.3 • W). By applying OPERA to multiple instruments, a time series of ozone profiles from 1996 to 2013 from a single robust algorithm can be created.

Overview of the O3M SAF GOME-2 operational atmospheric composition and UV radiation data products and data availability

“…A detailed description of the GOME-2 total ozone column algorithm can be found in Van Roozendael et al (2006), Loyola et al (2011) and Hao et al (2014). Figure 1 shows one example of the total ozone product: The Antarctic ozone hole for 2 October 2014 measured from GOME-2A and GOME-2B when the minimum total ozone column reached was around 120 DU.…”

Simultaneous assimilation of ozone profiles from multiple UV-VIS satellite instruments

“…For the retrievals used in this research, the radiance measurements are binned in the crosstrack and along-track directions such that the ground pixels measure approximately 160 km ×160 km. The ozone profiles for GOME-2 are retrieved with the OPERA retrieval algorithm, which is described in van Peet et al (2014). We increased the number of layers in this study from 16 to 32 for more accurate radiative transfer model results.…”

“…Figure 6 shows the global validation results for the 4 years of the assimilation period (2008-2011) of the GOME-2 and OMI profiles with ozone sondes downloaded from the World Ozone and Ultraviolet Radiation Data Centre (WOUDC, WMO/GAW, 2016). The validation methodology has been described in van Peet et al (2014), and the main characteristics are the following. Only cloud-free (cloud fraction < 0.2) retrievals have been used, the sonde launch location should be located in the pixel footprint, and the satellite overpass time should be within 3 h of sonde launch.…”

Nadir ozone profile retrieval from SCIAMACHY and its application to the Antarctic ozone hole in the period 2003–2011

“…An alternative approach is to 15 use satellite measurements in nadir mode by high-resolution spectrometers in the thermal IR, like IASI and TES, and in the UV/VIS, like GOME, GOME-2 (e.g. Cai et al, 2012;van Peet et al, 2014;Keppens et al, 2015;Miles et al, 2015). OMI (e.g.…”

“…This amounts Channel 2 to obtaining the state of the atmosphere by using the radiative transfer model and inversion technique iteratively till the model atmosphere matches the measurement. For a comprehensive algorithm overview and retrieval configuration, along with a description of the evaluation of the algorithm and the application to GOME-2 data, we refer to (Mijling et al, 2010;van Peet et al, 2014). The configuration chosen for all the retrievals are tabulated in Table 2.…”