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. (2004). 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 found and on average agree to within ±1%. Very little seasonal variations in the observed differences are observed. In the polar region and at high solar zenith angles, however, a positive bias varying between 5 and 8% is found. 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.

Measurements of total and tropospheric ozone from IASI: comparison with correlative satellite, ground-based and ozonesonde observations

“…Both Dobson and Brewer instruments present similar performances (Kerr et al, 1988). The Dobson and Brewer total ozone measurements have already been used for the validation of satellite derived total ozone measurements (Weber et al, 2005;Balis et al, 2007). For the comparisons with IASI total ozone columns, we used all the Dobson and Brewer data derived from direct sun and zenith sky observations available for 2008 from the WOUDC archives.…”

SO<sub>2</sub> Retrieval from SCIAMACHY using the Weighting Function DOAS (WFDOAS) technique: comparison with Standard DOAS retrieval

“…The WFDOAS method has been first demonstrated to be applicable to retrievals of trace gas columns in the near infrared region of SCIAMACHY (Buchwitz et al, 2000). It is also being used for direct retrieval of vertical O 3 amounts Weber et al, 2005;Bracher et al, 2005). It is distinct from the SDOAS by the use of wavelength-dependent weighting functions, which describe the relative radiance change due to a vertical profile change.…”

“…The DOAS fitting utilized a non-linear least square method, including wavelength shifts and squeeze for the nadir measurement spectrum to make the direct comparison between measured and modeled radiances (ColdeweyEgbers et al, 2005;Weber et al, 2005). After DOAS fitting the retrieved ozone column was compared with that of the reference scenario.…”

A long‐term stratospheric ozone data set from assimilation of satellite observations: High‐latitude ozone anomalies

“…Total (column) ozone (TO3) is not a central topic of our study; nevertheless it is interesting to establish how well it is reproduced in our assimilated data set. Here we compare TO3 in our assimilated data set to observations from the GOME instrument onboard the ERS 2 satellite [ColdeweyEgbers et al, 2005;Weber et al, 2005] and from the SCIAMACHY instrument on ENVISAT [Bovensmann et al, 1999;Bracher et al, 2005], as well as to the merged TOMS/SBUV data set [Stolarski and Frith, 2006].…”

“…A continuous data set of satellite-observed TO3 is provided by the TOMS/SBUV merged data set using TOMS (Total Ozone Mapping Spectrometer) and SBUV observations from 1979 to 2008. However, in order to validate our data set against completely independent observations, here we select data from GOME and SCIAMACHY instruments, which have been flying on ESA research satellites [Bracher et al, 2005;Weber et al, 2005]. GOME provided global ozone data from 1995 to mid-2003, while SCIAMACHY has been in continuous operation since mid-2002.…”