1 / 26

Envisat RA-2 Range Cross-calibration Michiel Otten

Envisat RA-2 Range Cross-calibration Michiel Otten. Envisat RA-2/MWR CCVT 6 th Plenary Meeting 25-27 March 2003. Envisat RA-2 GDR (pre-)processing RA-2 Measurement Corrections on GDR RA-2 Range Cross-Calibration RA-2 Residual and Near Coast Performance Envisat Orbit Validation

tracen
Download Presentation

Envisat RA-2 Range Cross-calibration Michiel Otten

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Envisat RA-2 Range Cross-calibrationMichiel Otten Envisat RA-2/MWR CCVT 6th Plenary Meeting 25-27 March 2003

  2. Envisat RA-2 GDR (pre-)processing RA-2 Measurement Corrections on GDR RA-2 Range Cross-Calibration RA-2 Residual and Near Coast Performance Envisat Orbit Validation Summary and Remarks Contents

  3. Check data for Quality indicator (record 2) and only used MCD bit 16. Editing of data done during range-bias estimation. Following corrections used from GDR: ECMWF Dry Troposphere (and IB) MWR Wet Troposphere Solid Earth and Pole Tide Envisat RA-2 GDR pre-processing 1/2

  4. Corrections replaced by own model: Mean Sea Surface: CLS01 Ionosphere: JPL-GIM Ocean and Load Tide: GOT00.2 Used a simple SSB model: 5% of SWH for Range Cross-Calibration Case 1 (later more) Envisat RA-2 GDR pre-processing 2/2

  5. Processed all Altimetry data for cycle 10, 11 and for cycle 12 until 19/12/03 Performed collinear analysis of altimeter data (used every 20th point) Used own orbit solution instead of CNES solution Edited data using a 3 sigma editing criteria and a 30 cm threshold. Envisat RA-2 GDR processing

  6. Envisat Cycle 10 data used (each 20th point) used rejected Latitude

  7. Checked the following corrections: ECMWF Dry Troposphere (IB) [looks ok] MWR Wet Troposphere [some issues] Ocean tide solution 1 and 2 [ok] DORIS Ionosphere correction [not ok] Also looked at SWH and found large number of measurements with zero/invalid wave height Only used cycle 10 data for measurement correction analysis RA-2 Measurement corrections on GDR

  8. Cycle 10 Ionosphere Correction (JPL-GIM) used rejected Correction (m)

  9. Cycle 10 Ionosphere Correction (DORIS) used rejected Correction (m) Correction in discrete steps of 1 mm Not shown large negative and positive values

  10. Cycle 10 Ionosphere correction cont’d Left figure JPL-GIM histogram right figure DORIS ionosphere histogram Green line used observations, red line rejected observations.

  11. Cycle 10 MWR Wet Troposphere correction used rejected Correction (m) Notice negative correction values

  12. MWR Wet Troposphere correction cont’d Left figure histogram of Wet Troposphere correction from ERS-2 MWR for cycle 78. Right figure histogram from Envisat MWR for cycle 10. Green line used observations, red line rejected observations.

  13. Cycle 10 SWH values on GDR 5% of SWH as SSB model for range cross-calibration case 1 (later more) Left figure SSB (or 5% of SWH) in meters vs latitude. Right figure histogram Green used observations, red rejected observations.

  14. Calibrated Envisat and ERS-2 relative to CLS01 MSS. Used DEOS RADS database for ERS-2 Altimetry cycle 78-79-80 Used DEOS ERS-2 orbit (intermediate) Replaced same corrections for ERS-2 as for Envisat, i.e., MSS (CLS01) , ocean-, load- tide (GOT00.2) and ionosphere (JPL-GIM) Envisat RA-2 Range Cross-Calibration

  15. RA-2 Range Cross-Calibration cont’d Case 1: ERS-2 – SSB BM-3 (RADS) ENVISAT – 5% SWH Case 2: No SSB for ERS-2 and Envisat Not yet tested: Delta-SSB model of Remko Scharroo (E-mail of 17.03.03). No significant time bias found ( <0.1ms for cycle 10 and ~0.2ms for cycle 11) *No DORIS tracking data for cycle 12.

  16. Envisat RA-2 Residual for Cycle 10

  17. Envisat RA-2 Residual for Cycle 10 cont’d Left figure Envisat RA-2 residual for cycle 10. Right figure ERS-2 Sea Level Anomaly for October 2002 from nng.esoc.de Same large scale features visible

  18. Envisat RA-2 1Hz data for cycle 10 used rejected Latitude

  19. Envisat RA-2 near coast performance used rejected Latitude

  20. Envisat RA-2 near coast performance cont’d used rejected Latitude

  21. Envisat RA-2 near coast performance cont’d used rejected Latitude

  22. Geopotential: GRIM5-C1 degree and order 70 Third bodies: Sun, Moon (J2) and all planets Non grav. forces: ANGARA (MSIS-90, HWM93) Reference frame: ITRF 2000 Estimated parm.: 5 day arc with overlap of first and last day Initial position and velocity Aerodynamic drag (4 times a day) Solar radiation once per arc Along and Cross CPR term per day Tracking data : SLR and DORIS Envisat Orbit Validation ESOC POD Models

  23. Envisat Orbit Validation ESOC Precise Orbit Comparison with CNES POE * * * * * * RMS difference in cm. Asterisk (*) indicates an Envisat manoeuvre

  24. Envisat Orbit Validation Radial Orbit Difference Radial orbit difference in cm. 10-3A does not contain the Envisat manoeuvre. Orbit comparison provided by NCL.

  25. Envisat Orbit Validation Table left shows XO residual for CNES POE and NCL solution (provided by NCL). Figure shows orbit difference between ESOC and CNES for a 3 day period in september 2002.

  26. Envisat range bias relative to ERS-2 estimated to be –1.119 m ± 5 mm (based on cycle 10 and 11) Found no significant timing bias. May reprocess GDR data with more editing using MCD flags or other quality indictors depending on outcome of this meeting. Will run range cross-calibration with delta-SSB model before EGS. Envisat radial orbit error estimated to be 2-3 cm for CNES POE and other solutions. Summary and Remarks

More Related