Welcome › Forums › Copernicus Marine User Forum › Ocean colour › Sentinel 3 Validation Team Ocean Colour meeting reports › S3VT-OC meeting summary: 23rd January 2019
23 January 2019 at 18:32 #1322Hayley Evers-KingModerator
S3VT-OC meeting summary: 23rd January 2019
Status of OLCI-B
- Level 1B data from OLCI-B was publically released on 12/12/2018.
- Details can be found in the product notice (https://www.eumetsat.int/website/wcm/idc/idcplg?IdcService=GET_FILE&dDocName=PDF_S3_PN_OLCI_L1.04&RevisionSelectionMethod=LatestReleased&Rendition=Web). This also covers OLCI-A.
- There is a negative drift in the OLCI-B along track geolocation, which has the potential for non-compliance with mission requirements, for cameras 2 and 5. However this drift is slowing and will be monitored.
- Spectral calibration acquisitions show a very close agreement, and excellent consistency both across the spectral range and with time.
- OLCI-B shows good comparison with MERIS (within 1%). OLCI-B is ~2% darker than OLCI-A, which has a bright bias.
- The 1020nm band is subject to a bright bias of around 4%.
- Vertical striping (periodic noise) is observed at the first 100 pixels at camera interfaces. A correction is under investigation.
- There are single anomalous pixels due to prompt particle events in the South Atlantic Anomaly.
- Quality investigations of L1B flags are ongoing, with no issues identified yet.
- Development of per pixel-uncertainty estimate is supported by activities starting in the S3 Mission Performance Centre.
Cyclic reports on the status of OLCI-A and B are available through: https://sentinels.copernicus.eu/web/sentinel/technical-guides/sentinel-3-olci/data-quality-reports
OLCI-B Yaw manoeuvres
- Solar diffusers are the primary radiometric standard for both OLCI instruments.
- Yaw manoeuvres provide an in-flight solar diffuser bidirectional reflectance distribution (BRDF) function. This can provide an accurate relative BRDF model compared to that determined pre-flight (Rahman).
- The placing of the diffusers is slightly different between OLCI-A and B (0.4 degrees). To account for this, additional analysis of the yaw manoeuvres was needed. This is now accomplished and a new model is coming for OLCI-B
Progress towards level 2 public release
- There will be a routine operations readiness review in the 2nd half of March, with the level 2 public release planned before this review.
- Major activities include the derivation of system vicarious calibration gains, and implementation of the alternative neural network for complex waters. Preliminary gains are in analysis.
- S3 OLCI/SYN Quality Working Group recommended organisation of a meeting to discuss matchup protocols for OLCI. Location of this meeting is in discussion but could take place alongside the International Ocean Colour Science (IOCS) meeting in April, or at S3VT in May. The meeting will seek to consolidate community based approaches for:
- In situ processing
- BRDF correction
- Band shifting
- In situ matching with satellite
- Adjustments based on water type
- Data screening (including flags)
- Statistics presentation (for intercomparison)
A question was raised as to whether the alternative neural network will replace the current complex water processor. It was confirmed that this will be the case.
- You must be logged in to reply to this topic.