Intercomparison of polar ozone profiles by IASI/MetOp sounder with 2010 Concordiasi ozonesonde observations

[摘要] Validation of ozone profiles measured from a nadir looking satelliteinstrument over Antarctica is a challenging task due to differences in theirvertical sensitivity with ozonesonde measurements. In this paper, ozoneobservations provided by the Infrared Atmospheric Sounding Interferometer(IASI) instrument onboard the polar-orbiting satellite MetOp are comparedwith ozone profiles collected between August and October 2010 at McMurdoStation, Antarctica, during the Concordiasi measurement campaign. The mainobjective of the campaign was the satellite data validation. With this aim 20zero-pressure sounding balloons carrying ozonesondes were launched duringthis period when the MetOp satellite was passing above McMurdo. This makesthe dataset relevant for comparison, especially because the balloons coveredthe entire altitude range of IASI profiles. The validation methodology andthe collocation criteria vary according to the availability of globalpositioning system auxiliary data with each electro-chemical cell ozonesondeobservation. The relative mean difference is shown to depend on the verticalrange investigated. The analysis shows a good agreement in the troposphere(below 10 km) and middle stratosphere (25–40 km), where the differencesare lower than 10%. However a significant positive bias of about10–26% is estimated in the lower stratosphere at 10–25 km, depending onaltitude. The positive bias in the 10–25 km range is consistent withpreviously reported studies comparing in situ data with thermal infraredsatellite measurements. This study allows for a better characterization ofIASI-retrieved ozone over the polar region during ozone depletion/recoveryprocesses.

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