1. OMI ST meeting 11 20-22 June 2006 Calibration working group

2. OMI ST Meeting 11, 20-22 June 2006Slide 2 Marcel Dobber, KNMI Calibration and algorithm WG’s Stray light Feedback level-2 to stray light algorithm and OPF work:  OMTO3  SO 2  Raman cloud Stripes in level-2 data  Fixed irradiance or composite irradiance

3. OMI ST Meeting 11, 20-22 June 2006Slide 3 Marcel Dobber, KNMI Calibration, algorithm, Data Systems WG’s Reprocessing:  Current schedule  Prerequisites

4. OMI ST Meeting 11, 20-22 June 2006Slide 4 Marcel Dobber, KNMI Calibration WG (1) UV1 characterisation and validation (Larry Flynn):  To be investigated: Stray light in asymmetrically illuminated scenes O 3 profile retrievals for nadir and off-nadir Irradiance goniometry: ok BSDF (Glen Jaross):  Central row BSDF is 2.5% too low, wavelength independent  Swath angle dependence BSDF: more work required for reliable correction

5. OMI ST Meeting 11, 20-22 June 2006Slide 5 Marcel Dobber, KNMI Calibration WG (2) Irradiance row dependence: ok High-resolution solar reference spectrum (Robert Voors):  Results presented, ongoing work  Spectral slit functions of instruments other than OMI are often insufficiently calibrated (SUSIM): assuming shape works reasonably well Diffuser features (Ruud Dirksen):  Difficult to characterise / parameterise (as expected)  Correction by calibration seems to be out of the question (as expected)

6. OMI ST Meeting 11, 20-22 June 2006Slide 6 Marcel Dobber, KNMI Calibration WG (3) Detector and electronics (Quintus Kleipool):  RTS / Bad and Dead Pixel Map: software and algorithm for dynamical updates (time-dependent OPF)  Non-linearity: Analysis of latest LED results looks ok, no issues LED works better than WLS  Gain ratios: LED works better than WLS, no issues

7. OMI ST Meeting 11, 20-22 June 2006Slide 7 Marcel Dobber, KNMI Calibration WG (4) Radiation damage effects (Gil Leppelmeier, Marcel Dobber):  OSIRIS (ODIN)600 km  OMI (EOS-Aura)700 km  GOMOS (ENVISAT)800 km Results to be confirmed

8. OMI ST Meeting 11, 20-22 June 2006Slide 8 Marcel Dobber, KNMI Calibration WG (5) Stray light:  LSA / USA vs spectral stray light algorithms Difficult but necessary to separate spectral and spatial  Plan for coming period has been defined  Diagnostics: Asymmetrically illuminated scenes (UV1, UV2, VIS) Channel overlap regions UV1-UV2 and UV2-VIS Cloud features UV1 L2 OMTO3, SO 2, Raman cloud