Validation of OMI total ozone using ground-based Brewer observations

Near-to-real time as well as archive quality Brewer total ozone observations, which are performed with well maintained and calibrated instruments over the NH have been used for the validation of the total ozone product of OMI. During the commissioning phase, the near-to-real time ground-based data, which are submitted to the WMO NH Ozone Mapping Centre within a few hours after observation, have been employed to check the behaviour of the OMI instrument as a function of measuring geometry. In addition the near-to-real time ground based data are also used as an early warning tool for the detection of possible problems during the operation of OMI. Archived ground-based data have been used to validate more than one year of OMI-TOMS and OMI-DOAS total ozone measurements. The comparisons show an agreement of better than 1% for the OMI-TOMS measurements and better than 2% for OMI-DOAS.