Pole-to-pole validation of GOME WFDOAS total ozone with groundbased data

Abstract

Abstract. This paper summarises the validation of GOME total ozone retrieved using the Weighting Function Differential Optical Absorption Spectroscopy (WFDOAS) algorithm Version 1.0. This algorithm has been described in detail in a companion paper by Coldewey-Egbers et al. (2005). Compared to the operational GDP (GOME Data Processor) V3, several improvements to the total ozone retrieval have been introduced that account for the varying ozone dependent contribution to rotational Raman scattering, includes a new cloud scheme, and uses the GOME measured effective albedo in the retrieval. In this paper the WFDOAS results have been compared with selected ground-based measurements from the WOUDC (World Ozone and UV Radiation Data Centre) that collects total ozone measurements from a global network of stations covering all seasons. From the global validation excellent agreement between WFDOAS and ground data was observed. The agreement lies within ±1%, and very little seasonal variations in the differences are found. In the polar regions and at high solar zenith angles, however, a positive bias varying between 5 and 8% is found near the polar night period. As a function of solar zenith angle as well as of the retrieved total ozone, the WFDOAS differences to ground polar data, however, show a much weaker dependence as compared to the operational GOME Data Processor Version 3 of GOME that represents a significant improvement. Very few stations carry out simultaneous measurements by Brewer and Dobson spectrometers over an extended period (three years or more). Simultaneous Brewer and Dobson measurements from Hradec Kralove, Czech Republic (50.2 • N, 15.8 • E) and Hohenpeissenberg, Germany (47.8 • N, 11.0 • E) covering the period 1996-1999 have been compared with our GOME results. Agreement with Brewers are generally better than with the simultaneous Dobson measurements and this may be explained by the neglect of stratospheric (ozone) temperature correction in the standard ozone retrieval from the ground.Correspondence to: M. Weber (weber@uni-bremen.de)

Attribution of stratospheric ozone trends to chemistry and transport: a modelling study

“…Here we show a comparison of modelled column ozone (TO3) to observations from the Total Ozone Mapping Spectrometer and Solar Backscatter UV (TOMS/SBUV) merged dataset (Stolarski and Frith, 2006), as well as the G. Kiesewetter et al: Attribution of stratospheric ozone trends GOME/SCIAMACHY/GOME2 merged dataset ("GSG" in the following) which has been compiled from observations made by the Global Ozone Monitoring Experiment (GOME) Weber et al, 2005), the Scanning Imaging Absorption Spectrometer for Atmospheric Chartography (SCIAMACHY) (Bovensmann et al, 1999;Bracher et al, 2005), and GOME2 (Callies et al, 2000) instruments. In the GSG merged data set the SCIAMACHY (2002-present) andGOME2 (2007-present) data have been adjusted to the GOME data record (1995-present) by determining a mean scaling factor (GOME2 and SCIAMACHY) and trend (SCIAMACHY only) in the monthly mean zonal mean ratios.…”

Total ozone trends from 1979 to 2016 derived from five merged observational datasets – the emergence into ozone recovery

“…The merged GOME, SCIAMACHY, and GOME-2A (GSG) total ozone time series (Kiesewetter et al, 2010;Weber et al, 2011Weber et al, , 2016 consists of total ozone data that were retrieved using the University of Bremen weighting function DOAS (WFDOAS) algorithm Weber et al, 2005). The most recent modification was in the GOME-2A data record.…”

Seven years of IASI ozone retrievals from FORLI: validation with independent total column and vertical profile measurements

“…The Dobson and Brewer stations considered in this paper and the criteria used for the selection of the stations have been extensively used in a series of validation papers of satellite total O 3 measurements (e.g., Weber et al, 2005;Balis et al, 2007a, b;Koukouli et al, , 2015. For the comparisons with IASI TOCs from FORLI, only direct sun observations are used as those are the most reliable for both the Dobson and the Brewer spectrophotometers, the latter offering an accuracy of about 1 % at moderate solar zenith angles (e.g., Kerr, 2002).…”