Geophysical validation of SCIAMACHY Limb Ozone Profiles

摘要

We discuss the quality of the two available SCIAMACHY limbozone profile products. They were retrieved with the Universityof Bremen IFE's algorithm version 1.61 (hereafter IFE), andthe official ESA offline algorithm (hereafter OL)versions 2.4 and 2.5. The ozone profiles were compared toa suite of correlative measurements from ground-based lidar andmicrowave, sondes, SAGE II and SAGE III (StratosphericAerosol and Gas Experiment).

To correct for the expected Envisat pointing errors, which have notbeen corrected implicitly in either of the algorithms, we applied aconstant altitude shift of -1.5 km to the SCIAMACHY ozoneprofiles.

The IFE ozone profile data between 16 and 40 km are biasedlow by 3-6%. The average difference profiles have a typicalstandard deviation of 10% between20 and 35 km.

We show that more than 20% of the SCIAMACHY official ESA offline (OL) ozoneprofiles version 2.4 and 2.5 have unrealistic ozone values, most of these arenorth of 15° S. The remaining OL profiles compare well to correlativeinstruments above 24 km. Between 20 and 24 km, they underestimateozone by 15±5%.