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

[摘要] This paper summarises the validation of GOME total ozone retrievedusing the Weighting Function Differential Optical AbsorptionSpectroscopy (WFDOAS) algorithm Version 1.0. This algorithm has beendescribed in detail in a companion paper by Coldewey-Egbers et al. (2005). Compared to the operational GDP (GOME DataProcessor) V3, several improvements to the total ozone retrievalhave been introduced that account for the varying ozone dependentcontribution to rotational Raman scattering, includes a new cloudscheme, and uses the GOME measured effective albedo in theretrieval. In this paper the WFDOAS results have been compared withselected ground-based measurements from the WOUDC (World Ozone andUV Radiation Data Centre) that collects total ozone measurementsfrom a global network of stations covering all seasons.From theglobal validation excellent agreement between WFDOAS and ground datawas observed. The agreement lies within ±1%, and very littleseasonal variations in the differences are found.In the polarregions and at high solar zenith angles, however, a positive biasvarying between 5 and 8% is found near the polar night period. As afunction of solar zenith angle as well as of the retrieved totalozone, the WFDOAS differences to ground polar data, however, show amuch weaker dependence as compared to the operational GOME DataProcessor Version 3 of GOME that represents a significantimprovement.Very few stations carry out simultaneous measurementsby Brewer and Dobson spectrometers over an extended period (threeyears or more). Simultaneous Brewer and Dobson measurements fromHradec Kralove, Czech Republic (50.2N, 15.8E) andHohenpeissenberg, Germany (47.8N, 11.0E) covering theperiod 1996-1999 have been compared with our GOME results.Agreement with Brewers are generally better than with thesimultaneous Dobson measurements and this may be explained by theneglect of stratospheric (ozone) temperature correction in thestandard ozone retrieval from the ground.

[学科分类] 大气科学