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Level 1.5 Processing Issues

Level 1.5 Processing Issues. Martin Bates RAL. Level 1.5 Processing Issues. Geolocation Current Status TSOL Jitter (CSOL-TSOL) correction Longterm TSOL Jitter Solution Comparisons with RGP Processing Upcoming Updates to Processing Processing Validation. Current Status.

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Level 1.5 Processing Issues

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  1. Level 1.5 Processing Issues Martin Bates RAL

  2. Level 1.5 Processing Issues • Geolocation • Current Status • TSOL Jitter (CSOL-TSOL) correction • Longterm TSOL Jitter Solution • Comparisons with RGP Processing • Upcoming Updates to Processing • Processing Validation

  3. Current Status • Level 1.5: Adhoc E-W geolocation correction • sinusoid (amplitude, phase, offset tunable) • ESU dependent • accurate to ~1 pixel, a bit worse N-S. • Level 2: fit to SEVIRI data (formerly MS7A) • decoupled from Level 1.5 • accurate to ~ 0.2 pixels (< 0.5 pixels) 09 Nov 2003

  4. TSOL Jitter • Predicted TSOL – actual TSOL • as used by IMPF • predicted TSOL (CSOL) from rotational model • Temporary scheme • data available on ftp server at EUMETSAT since 16 February • coverage > 99.6 % (dropouts at sun-satellite colinearity) • copy across and use as correction to E-W geolocation • ggsps correction for early April.

  5. TSOL Jitter data spikey – needs filtering 14 Nov 2003

  6. Smoothed TSOL Jitter Result of median filter ( 1 minute) One spike in close-up

  7. Corrected Data (15 Nov 2003) no filtering

  8. am/pm Systematic 15 Nov 2003

  9. TSOL Jitter Correction 23 March 2004

  10. TSOL Jitter Correction 23 March 2004 am/pm systematic still present 23 March 2004 offset slightly different

  11. Long term solution • Robustness of ftp server solution in question. • Longer term solution: • append (TSOL Jitter) value to GERB packet • correction algorithmically no different • improved reliability and timeliness of information • Timescale: 6-12 months. • requires Engineering Change Proposal (for IMPF and UMARF) • still to be approved by EUMETSAT • SEVIRI reprocessing ? • can then get values for before 16 Feb.

  12. RGP Comparisons • Process data from 14-16 Nov 2003 using TSOL jitter correction. • Compare to RGP geolocation (high CPU fit) comparing to SEVIRI.

  13. North-South Compression 15 Nov 2004 11:56:58 (SW) Still there ! N/S offset not perfect for these data

  14. Quasi-Rotation 15 Nov 2004 11:56:58 (SW) Also still there ...

  15. Retune Optical Model ? 1. Could be due to local deformations in one of the mirrors – but no estimate of possible sizes of effects 2. Image ratio plots  more structure in GGSPS plot GGSPS RGP

  16. Geolocation Plans • Interim TSOL Jitter Correction (April) • Long term TSOL Jitter Correction • for improved robustness • still to be approved, end of year ? • Optical Model – tune using RMIB info • Axis misalignments • MSG spin to MSG structure • large (~0.3 ?) • changes at each manoeuvre • action on EUMETSAT to investigate • Mirror Side Effects (non-parallel N/S ?)

  17. Upcoming Processing Updates • New BAT, BBRAD tables • but may be coordinated with data release • Offline gains (stray light & moon avoidance) • depends on gain stability: • if update < once per month • use offline gains (data table) • if update more frequently • avoid problem regions or • use gains calculated at good times of day • startup problems & time dependent processing • Stray Light Correction TBD • Numerous minor updates • NCR fixes • additions (diagnostics) to NANRG product • confidence flag definitions

  18. Processing Validation • Geolocation Validation • Comparisons with SEVIRI / RGP geolocation (RMIB) • Overall Validation • series of unit and integration tests done (test data, limited set of circumstances) • step by step validation using real data and checkpoint files suggested (validation plan) – TBD • monitoring of calibration parameters using engineering report (Imperial).

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