GOMOS ozone profile validation using ground-based and balloon sonde measurements

Abstract

Abstract. The validation of ozone profiles retrieved by satellite instruments through comparison with data from groundbased instruments is important to monitor the evolution of the satellite instrument, to assist algorithm development and to allow multi-mission trend analyses.In this study we compare ozone profiles derived from GO-MOS night-time observations with measurements from lidar, microwave radiometer and balloon sonde. Collocated pairs are analysed for dependence on several geophysical and instrument observational parameters. Validation results are presented for the operational ESA level 2 data (GOMOS version 5.00) obtained during nearly seven years of observations and a comparison using a smaller dataset from the previous processor (version 4.02) is also included.The profiles obtained from dark limb measurements (solar zenith angle >107 • ) when the provided processing flag is properly considered match the ground-based measurements within ±2 percent over the altitude range 20 to 40 km. Outside this range, the pairs start to deviate more and there is a Correspondence to: J. A. E. van Gijsel

Comparison of GOME-2/Metop-A ozone profiles with GOMOS, OSIRIS and MLS measurements

“…The vertical resolution of the ozone profile retrieved using OPERA is between 7 and 15 km (van Peet et al, 2014;Meijer et al, 2006). Figure 1 shows averaging kernels for a one example retrieval at pixel (42.7 • N, 44.5 • W) on 10 February 2010.…”

“…The ozone profiles are generated by the OPERA algorithm developed at the Royal Netherlands Meteorological Institute (KNMI). The algorithm uses an iterative approach when fitting state vector (ozone profile) to the measured radiances using an optimal estimation method (Rodgers and Connor, 2003) and the LI-DORTA radiative transfer model (van Oss and Spurr, 2002). The ozone climatology by McPeters et al (2007) is used as a priori data.…”

“…We have used the GOME-2 ozone profiles with a quality processing flag indicating successful retrieval (Tuinder, 2015). The ozone profile is given as partial columns A. Kauppi et al: GOME-2/Metop-A ozone profile comparison 251 in Dobson units (DU) at 40 layers between logarithmically spaced pressure levels between the surface and 0.001 hPa (van Oss et al, 2014;Tuinder, 2015). The cloud-top pressure replaces the surface pressure level in cloudy and partially cloudy scenes.…”

“…Our data set covers years 2008-2011 retrieved with nine OPERA software versions 1.14-1.24. The Level 2 ozone profile product contains a priori profile, averaging kernels, full error covariance matrix, retrieval noise covariance matrix and other relevant information (van Oss et al, 2014;Tuinder, 2015). We have used the GOME-2 ozone profiles with a quality processing flag indicating successful retrieval (Tuinder, 2015).…”

“…The impact of the first guess on the retrieved profiles as well as the choice of the ozone climatologies and ozone cross-sections were also analyzed. After the further development of OPERA, van Peet et al (2014) have shown that the algorithm can also be applied to other nadir instruments measuring in UV-VIS range such as OMI and SCIAMACHY.…”