CONCLUSIONS

1. CONCLUSIONS • Statistically relevant quantification and characterisation of errors under the most relevant conditions is not possible on the basis of the currently available data set. • First qualitative indications are as follows: • GOMOS • Initial indications are that O3 data acquired in dark limb are reasonable (in particular low bias), and under other circumstances the data quality is poor. The errors reported in the poor cases are not realistic, and it is therefore recommended not to distribute the current bright-limb concentration/error data. • Initial indications are that density retrievals are reasonable. The mixing of model and retrieved data does not allow to judge the quality of the temperature retrieval, but first indications are that the HRTP is superior to the LRTP • MIPAS • No ‘show stopping’ problems have been found in the sparse p, T, O3, H2O intercomparisons that could be made. • SCIAMACHY • Total Ozone from version 3.53 shows deviations but is an important improvement. • NO2 columns from version 3.53 show excessive deviations in many of the collocations and it is recommended not to distribute this version. • The quality of version-4 NO2 columns cannot yet be independently assessed. • Scientific retrieval studies have provided an indication of the potential of accurate retrievals.