Calibration & 0 -1 b data processing Marcel Dobber (KNMI) OMI ST meeting 11 20 -22 June 2006
Contents l l l l l Radiometric + irradiance. Status CCD detectors GDPS status. OPF status Processing in ps 0002. Reprocessing end 2006. TMCF + PGE status. Future plans. Conclusions. OMI ST Meeting 11, 20 -22 June 2006 Marcel Dobber, KNMI Slide 2
Calibration team l l l l Robert Voors (KNM) Quintus Kleipool (KNMI) Marcel Dobber (KNMI) Glen Jaross (SSAI / NASA) Ruud Dirksen (KNMI / SRON), will leave calibration team per 1 July 2006 to work on NO 2 with Henk Eskes Werner Dierssen (KNMI / Triop. Sys), left per 1 May 2006 Johan de Vries (DS), left per 1 January 2006 OMI ST Meeting 11, 20 -22 June 2006 Marcel Dobber, KNMI Slide 3
Irradiance 31 DEC 2004 Old situation, OPF 7, ps 0001. OMI ST Meeting 11, 20 -22 June 2006 Marcel Dobber, KNMI Slide 4
Irradiance 31 DEC 2004 l l Old situation, OPF 8 -20, ps 0002. These radiometric keydata were still exclusively based on onground measurements. OMI ST Meeting 11, 20 -22 June 2006 Marcel Dobber, KNMI Slide 5
Irradiance l l Current situation, OPF 21 -31, ps 0002. In these radiometric keydata corrections obtained from in-flight comparisons have been used. OMI ST Meeting 11, 20 -22 June 2006 Marcel Dobber, KNMI Slide 6
Status CCD detectors: Pixels with permanently increased dark current as function of time l 6 February 2006 (571 days after launch) ¾ UV: 17. 0% of all unbinned pixels (image area) ¾ VIS: 17. 6% of all unbinned pixels (image area) OMI ST Meeting 11, 20 -22 June 2006 Marcel Dobber, KNMI Slide 7
GDPS status (1) l l v 0. 9. 12 (26 August 2005), not used in ps 0002: ¾ Same version as 0. 9. 13, but with a bug: the flagged transient pixels were not excluded in the calculation of the irradiance average. v 0. 9. 13 (31 August 2005): ¾ Added possibility for fill values OPF. ¾ New DEM saturation flagging algorithm. ¾ New transient pixel flagging algorithm replaces old one. ¾ Fixed bug in calculation global products from spatial zoom-in products. OMI ST Meeting 11, 20 -22 June 2006 Marcel Dobber, KNMI Slide 8
GDPS status (2) l v 0. 9. 14 (1 March 2006): ¾ New algorithm for irradiance goniometry (d. IRRAD) replaces the old one. l l l ¾ ¾ l See TN-OMIE-KNMI-754, issue 3, 1 February 2006. Wavelength dependence is now also dependent on azimuth and elevation angles and row. Maximum 2 nd order polynomial for wavelength dependence. Row dependence not fitted, but stored per row in OPF. Wavelength dependence not per subchannel. Possibility to bypass the d. IRRAD algorithm in the algorithm bypass list. Intended LUT change (LED linearity measurements). v 0. 9. 15 (3 March 2006), not used in ps 0002. See also v 0. 9. 14: ¾ LUT change (LED linearity measurements) was not updated. v 0. 9. 14 was never used, but immediately replaced by v 0. 9. 15. OMI ST Meeting 11, 20 -22 June 2006 Marcel Dobber, KNMI Slide 9
GDPS status (3) l v 0. 9. 16 (7 June 2006, TBC): ¾ New algorithm for USA / LSA stray light correction replaces the old one. l l ¾ See TN-OMIE-KNMI-792, issue 2, 30 March 2006. See TN-OMIE-KNMI-814, issue 1, 30 May 2006. Predefined shapes as function of column in OPF for LSA and USA for earth, sun, WLS. Row dependence with linear interpolation between LSA and USA. New algorithm for spectral stray light correction replaces old one. l l See TN-OMIE-KNMI-802, issue 1, 27 March 2006. Row dependence with preset (OPF) windows for stray light source and target regions. OMI ST Meeting 11, 20 -22 June 2006 Marcel Dobber, KNMI Slide 10
Changes to OPF’s l OPF sets: ¾ OPFs 21 -30 (GDPS 0. 9. 13) l l l OPF Entries Changes: New entries for new transient pixel flagging algorithm. New entries for DEM saturation flagging algorithm. Added spectral slit function parameterisation data. Changed OPF cross-sections used for spectral calibration. Changed (slightly) spectral calibration parameters. Changed radiometric keydata without changing BSDF. Changed fallback dark images. Changed BDPM. Changed electronic non-linearity parameters. Changed threshold indicator non-linearity Changed dark current temperature correction parameters. OMI ST Meeting 11, 20 -22 June 2006 Marcel Dobber, KNMI Slide 11
Changes to OPF’s ¾ OPF 31 (GDPS 0. 9. 15) l ¾ New entries for new irradiance goniometry algorithm (see TNOMIE-KNMI-818, issue 1, 18 April 2006). OPF ? ? (GDPS 0. 9. 16) l l l New entries for LSA / USA stray light algorithm. New entries for spectral stray light algorithm. Updated radiometric calibration keydata. - l Updated swath angle dependent radiometric keydata - l l l Central row BSDF may also be changed (TBD) BSDF swath angle dependence will not be changed New dark image data. Possibly new BDPM (RTS, see TN-OMIE-KNMI-791, issue 1, 30 January 2006). Possibly new non-linearity. OMI ST Meeting 11, 20 -22 June 2006 Marcel Dobber, KNMI Slide 12
Reprocessing in ps 0002 OMI ST Meeting 11, 20 -22 June 2006 Marcel Dobber, KNMI Slide 13
Reprocessing end 2006 l l l Required for reprocessing end 2006, as far as calibration is concerned (i. e. list may not be complete!): ¾ GDPS 0. 9. 16, delivered 19 -23 June 2006. ¾ OPF for GDPS 0. 9. 16 (see one of previous slides). ¾ TDOPF software + system tuned and optimised for reprocessing. ¾ Integrated TMCF PGE’s (see next slide). Stray light parameters will be optimised as good as possible, but further changes in the future can not be excluded. Time-dependent functions will be set constant in TDOPF, except for: ¾ Background images. ¾ BDPM (which includes RTS). OMI ST Meeting 11, 20 -22 June 2006 Marcel Dobber, KNMI Slide 14
TMCF and TMCF PGE’s l TMCF and ODPS very stable: ¾ ¾ l l upgrade operating system. new storage facility. Open work list on TMCF completed. TMCF PGE’s: ¾ Splitter for Instrument Configueration ID’s. ¾ Averager for Instrument Configuration ID’s. ¾ Automated Analysis PGE (basic analyses). ¾ Dark signal median calculation (this one will be used for the reprocessing of end 2006). ¾ Irradiance azimuth and elevation angle dependence. OMI ST Meeting 11, 20 -22 June 2006 Marcel Dobber, KNMI Slide 15
TMCF and TMCF PGE’s l TMCF PGE’s (continued): ¾ Dark current as function of orbit phase. ¾ Dark current. ¾ RTS. ¾ BDPM. ¾ Spectral calibration (using correlation method). ¾ False-RGB image calculation. ¾ False-RGB image visualisation. ¾ Quality Flag summary. ¾ Visualisation (produces some 500 plots). Colours: PGE integrated in TMCF and running, but a new version is ready for integration. PGE ready and waiting for integration in TMCF. OMI ST Meeting 11, 20 -22 June 2006 Marcel Dobber, KNMI Slide 16
Background images used in reprocessing l l The OPF background images will be updated with a frequency of once per day using a median calculation algorithm. Once per day is a compromise between: ¾ Large vs smaller data amounts for TDOPF system. ¾ Number of background images available to reduce measurement noise sufficiently. l l ¾ l Per earth ICID 5+5 images per orbit, provided no passage through SAA, for sun measurements 77 images per orbit. Per earth ICID (5+5)*14=140 images per day (minus SAA), for sun measurements 77 images per day. Once per week is not sufficient, given the rate at which the CCD is hit by high-energetic protons. Median to exclude pixels with large deviations. OMI ST Meeting 11, 20 -22 June 2006 Marcel Dobber, KNMI Slide 17
Plan for OPF for GDPS 0. 9. 16 l l l Optimise LSA / USA and spectral stray light parameters. Adapt radiometric calibration parameters. GDPS 0. 9. 16 + OPF in ps 9999 (8 weeks Sept-Oct. 2006): ¾ l L 1 and L 2 to provide feedback. After this GDPS 0. 9. 16 + OPF are ready for reprocessing. OMI ST Meeting 11, 20 -22 June 2006 Marcel Dobber, KNMI Slide 18
Future plans l l l Stripes in L 1 and L 2 data after reprocessing: situation will be considerably better. Continue to monitor potential optical degradation behaviour using WLS and solar spectra. Continue to monitor CCD detector degradation behaviour. Further optimise convoluted high-resolution solar reference spectrum w. r. t. measured solar irradiance. Continue validation Earth reflectances (including swath angle dependence), BSDF structures, BSDF interchannel jumps (especially after stray light changes). OMI ST Meeting 11, 20 -22 June 2006 Marcel Dobber, KNMI Slide 19
Conclusions l OMI performance and calibration are in good shape. ¾ ¾ l Calibration data gap March-May 2006 due to FMM anomaly investigation. Stray light parameters must be optimised, plans for this are in place. Working towards reprocessing end 2006: ¾ ¾ ¾ GDPS 0. 9. 16 + OPF. TDOPF, including dynamic background correction and dynamic RTS identification (which will flow into BDPM). TMCF + PGE’s. OMI ST Meeting 11, 20 -22 June 2006 Marcel Dobber, KNMI Slide 20
Recent documents l l See CTB website, calibration (https: //omiwww. gsfc. nasa. gov/ctbweb/OMICTB_Configuration_Tracking_ Board. md). Ozone Monitoring Instrument Calibration, IEEE Transactions on Geoscience and Remote Sensing, vol. 44, no. 5, May 2006, 1209 -1238. Prelaunch characterization of the Ozone Monitoring Instrument transfer function in the spectral domain, Applied Optics, vol. 45, no. 17, 10 June 2006, 3972 -3981. Method of calibration to correct for cloud-induced wavelength shifts in the Aura satellite’s Ozone Monitoring Instrument, Applied Optics, vol. 45, no. 15, 20 May 2006, 3652 -3658. OMI ST Meeting 11, 20 -22 June 2006 Marcel Dobber, KNMI Slide 21
OMI ST Meeting 11, 20 -22 June 2006 Marcel Dobber, KNMI Slide 22
UV part OMI ST Meeting 11, 20 -22 June 2006 Marcel Dobber, KNMI Slide 23
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