Global validation of ENVISAT ozone profiles using lidar measurements

Abstract

Satellite sensors provide global measurements of ozone concentration that can be used to study the effects of the implementation of the Montreal Protocol. However, a key issue in deriving long-term ozone trends from successive satellite instruments is inter-comparability. Ground-based measurements offer continuous time series, but only at a few locations. The combination of ground-based measurements with satellite data is therefore an effective means to evaluate satellite instrument inter-comparability. In this study, we present validation results of ozone profiles from three atmospheric sensors onboard ENVISAT by comparison with lidar measurements. Results for the SCIAMACHY ozone profiles (version 3.01) show reasonable agreement with ground-based measurements (0 to −20%). The MIPAS full-resolution (version 4.61) dataset has good agreement with lidar (0 to 10%), whereas a small positive bias (up to 20%) was found for the MIPAS reduced-resolution prototype data. GOMOS dark-limb data (version 5.00) agree very well (0 ± 5%) with the correlative data, but underestimate ozone concentration at the polar regions.

Acknowledgements

These studies have been performed in the framework of the ENVISAT quality assessment with lidar (EQUAL) project, which was financed by the European Space Agency. The authors would also like to thank the members of the GOMOS, MIPAS and SCIAMACHY quality working groups for their inputs and discussions. We also acknowledge the feedback from the anonymous reviewer, which has provided valuable improvements to this manuscript.