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
OVERVIEW SCIAMACHY OL 3.0 LIMB OZONE PROFILES DATA DESCRIPTION METHODOLOGY INDIVIDUAL OZONE PROFILE COMPARISONS ALTITUDE SHIFT TIME SERIES VERTICAL STRUCTURES CONCLUSION
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
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
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.
ALTITUDE SHIFT (1) SCIAMACHY previous versions of limb O3P : De Clercq et al., ESA SP-572, 2005.
ALTITUDE SHIFT (2) SCIAMACHY OL 3.0 Limb O3P : Zonal Structure
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.
TIME SERIES
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
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?)