1 / 9

AATSR Level 1b Processing: Status of Open Issues from the Calibration Review

AATSR Level 1b Processing: Status of Open Issues from the Calibration Review. Andrew R. Birks Rutherford Appleton Laboratory Chilton, Didcot Oxfordshire OX11 0QX UK ENVISAT Validation Workshop, ESRIN, Frascati 9 - 13 December 2002. Status of Open Issues from the Calibration Review.

rusti
Download Presentation

AATSR Level 1b Processing: Status of Open Issues from the Calibration Review

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. AATSR Level 1b Processing: Status of Open Issues from the Calibration Review Andrew R. Birks Rutherford Appleton Laboratory Chilton, Didcot Oxfordshire OX11 0QX UK ENVISAT Validation Workshop, ESRIN, Frascati9 - 13 December 2002

  2. Status of Open Issues from the Calibration Review • VISCAL algorithm • Level 1B Software Problem Reports • Auxiliary files • Potential L1b enhancements

  3. VISCAL algorithm: • Original VISCAL algorithm did not work with real AATSR data because of undocumented differences in VISCAL monitor sampling between ATSR-2 (basis of test data) and AATSR • Solution: New algorithm (update to DPM) and new PC1 file. • PP updated July 02 • OP update pending (integration problems have delayed release) • VISCAL GADS will be absent from OP products until this revision is operational

  4. Software Problem Reports (1) • SPR 1: Permutation of Auxiliary Temperatures in SPH • Closed: Corrected in the OP • SPR 2: Not applicable to Operational Processor • SPR 3: Typo in SPH field name • Closed: Corrected in the OP • SPR 4: SPH _mid_ parameters not compliant with DPM • Closed: Corrected in the OP • SPR 5: Discrepancy in final record of ADS #4 • Open but set aside for the present. Requires more information about the code. • SPR 6: Not applicable to Operational Processor

  5. Software Problem reports (2) • SPR 7: Invalid scan in OP not in PP • Closed. Corrected in the IPF (Investigation of this problem also revealed an error in the DPM and PP; further review required in the longer-term) • SPR 8: Cosmetic fill missing from solar angles • Open. OP contractor need more time to add missing DPM step. A work-around to address the impact of this problem on cloud clearing is in place. Review of OP code use of solar angles also required.) • SPR 9: Invalid scans not flagged in SQADS • Closed . Corrected in the OP (related to SPR 7) • SPR 10: Cosmetic fill missing from nadir view scan numbers • Closed. Corrected in the OP

  6. Auxiliary files: • Only 3 required revision at this stage: • ATS_INS_AX (to prevent spurious BBU temperature validation warnings): disseminated to PDS 29/10/02 • ATS_PC1_AX (for new VISCAL algorithm): will be introduced with new VISCAL code • ATS_CH1_AX (misalignment corrections, AOCS parameters and regridding tolerances): disseminated to PDS 14/11/02. May need further iteration in future

  7. Proposed enhancements (1) • Exception flags • Pixel exception values are small negative values • At night, noise in the visible channels can mimic exception values • Causes confidence flags to be wrongly set • Potential solution: modify internal exception values • Possible methods to address this problem are being evaluated in the PP. Schedule for implementation in PP and OP not yet established

  8. Proposed enhancements (2) • Regridding • Unfilled pixels in forward view caused by interaction of x - y geolocation errors with regridding algorithm changes • Modify x - y geolocation algorithm to reduce errors • Changes to CH1 file based on detailed review of X-y differences have significantly reduced incidence of cosmetic fill voids in forward view. Therefore a change to the algorithm itself is no longer considered a priority at this stage.

  9. Proposed enhancements (3) • The present VISCAL algorithm assumes consolidated data, and only finds the VISCAL peak following the time of the OSV in the Main Product Header • A further revision to VISCAL search algorithm is therefore required to cope with the NRT data currently being distributed, in which peaks may precede the OSV • Prototyped, but documents and TDS not yet submitted to OP contractor (include in next “batch” of changes).

More Related