1st post launchSCIAMACHY calibration & Verification MeetingL1bAstrium Friedrichshafen Germany24 July 2002

First level 1b Sun mean reference (SMR) analysis

ContentRelated Verification Tasks What has been looked at so far Orbit and State specifics First resultsConclusions

Related Verification TasksL1. 10.01: Range checking of various SMR record parameters L1. 10.02: Comparison of SMRs from different sourcesL1. 10.03: Comparison of in-flight and on-ground diffuser patternsL1. 02.03: Radiance sensitivity parameters unchanged

What has been looked at so far (1)L1. 10.01: Range checking of various SMR record parameters Wavelength of the sun spectrumMean sun reference spectrumRelative radiometric precision of SMRRelative radiometric accuracy of SMRDiffuser/small aperture etalonAverage mirror positions/elevation anglesMean value of the corresponding PMD valuesPMD out of band signalDoppler shift

What has been looked at so far (2)L1. 02.03: Radiance sensitivity parameters unchangedTo calculate the absolutely calibrated solar reference spectrum, a number of on-ground derived key-data is neededWhen comparing the calculated SMR (as from 1b processor) against a literatureValue, this tells us indirectly whether we have to expect changes in some of our Key-data.

Orbit and state specificsStates: State ID 62 (ESM diffuser) Orbits 798, 814, 1597 For orbits 798 and 814 pre-defined state parameters have been commanded,which may lead to problems in the interpretation of absolutely calibrated spectra, because the diffuser is partly obstructed by the stiffening/mounting ring.For orbits 1597 so called beta-flight state configuration was commanded, explicitly avoiding obstruction of the diffuser

First Results (1)Can all this deviation be explained by the obstruction?Have some key-parameters changed? Other explanations?

First Results (2)Good agreement in channels 1,2 and 5 Factor of 2 in channels 3,4 and 6Huge deviations in channel 7 and 8

Time - Normalisation problem (1b processor)THIS IS ICE

First Results (3)Good agreement in channels 1 to 6 although it is not yet perfect.We first have to apply better in-flight calibration (Leakage, wavelength).Channels 7 and 8 are just bad due to ice problem.

ConclusionsFixing of in-flight auxiliary files for leakage current and spectral calibration Looking at the remaining 1b SMR ADS record fields (first of all still based on state 62) Comparison of different sources of SMR Derivation of diffuser patterns and comparison of on-ground ones Repair of time-normalisation problem in 1b processor