1. Coralie.DeClercq@aeronomie.be, J-C.Lambert@aeronomie.be Ground-based validation of SCIAMACHY OL 3.0 Ozone Profile Data and Estimation of Altitude Shift by Cross-correlation Method SCIAMACHY Pointing Meeting, Bremen, 30 November 2006 Coralie DE CLERCQ, Pierre GERARD, José GRANVILLE, and Jean-Christopher LAMBERT Belgian Institute for Space Aeronomy (IASB-BIRA), Brussels

2. Coralie.DeClercq@aeronomie.be, J-C.Lambert@aeronomie.be OVERVIEW SCIAMACHY OL 3.0 LIMB OZONE PROFILES DATA DESCRIPTION METHODOLOGY INDIVIDUAL OZONE PROFILE COMPARISONS ALTITUDE SHIFT TIME SERIES VERTICAL STRUCTURES CONCLUSION

3. Coralie.DeClercq@aeronomie.be, J-C.Lambert@aeronomie.be DATA DESCRIPTION SCIAMACHY OL 3.0 LIMB OZONE PROFILES Limited data set retrieved at DLR NETWORKS OF GROUND-BASED INSTRUMENTS SCIAMACHY collocations with correlative data at : 12 ozonesonde stations 6 lidars

4. Coralie.DeClercq@aeronomie.be, J-C.Lambert@aeronomie.be METHODOLOGY (I) Individual ozone profile comparisons Altitude Shift Method of cross-correlation Time series Identify time periods where statistical analysis is relevant Vertical structure For homogeneous time periods

5. Coralie.DeClercq@aeronomie.be, J-C.Lambert@aeronomie.be INDIVIDUAL OZONE PROFILE COMPARISONS Altitude pointing shift Majority : decreased altitude shift A few : shifted downward Paramaribo : shifted upward Ozone maximum SCIAMACHY reports lower ozone values.

6. Coralie.DeClercq@aeronomie.be, J-C.Lambert@aeronomie.be ALTITUDE SHIFT (1) SCIAMACHY previous versions of limb O3P : De Clercq et al., ESA SP-572, 2005.

7. Coralie.DeClercq@aeronomie.be, J-C.Lambert@aeronomie.be ALTITUDE SHIFT (2) SCIAMACHY OL 3.0 Limb O3P : Zonal Structure

8. Coralie.DeClercq@aeronomie.be, J-C.Lambert@aeronomie.be ALTITUDE SHIFT (3) SCIAMACHY 3.0 Limb O3P : Meridian Structure Mean altitude shift strongly reduced <1km (1.5to 3km for previous versions) Zonal and meridian structures persist. Profiles are suitable for preliminary validation.

9. Coralie.DeClercq@aeronomie.be, J-C.Lambert@aeronomie.be TIME SERIES

10. Coralie.DeClercq@aeronomie.be, J-C.Lambert@aeronomie.be VERTICAL STRUCTURES Good agreement within 10% level except : Under-estimation of ozone maximum Larger negative differences at Paramaribo (Remaining altitude shift problems?) Underestimation around 40km in comparisons with lidar data

11. Coralie.DeClercq@aeronomie.be, J-C.Lambert@aeronomie.be CONCLUSION Ground-based analysis of SCIAMACHY limb ozone profile OL 3.0 Collocations found with 12 O3S and 6 lidars Known altitude pointing problem : Mean altitude shift < 1km (1.5 and 3km previously) Zonal and meridian dependences of pointing error exist. Profile are suitable for a preliminary validation Time series and vertical structures : Mean relative difference often fits within the ±10% level, except: Underestimation of ozone at its maximum Larger negative differences with a maximum at Paramaribo (Remaining altitude shift problems?)