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GOES-16 ABI Level 1b and Cloud and Moisture Imagery (CMI) Product Maturity Notice

June 1, 2017

Provisional Product Maturity Achieved

Read-Me for Data Users

ABI ptm The GOES-R Peer Stakeholder - Product Validation Review (PS-PVR) for ABI L1b Provisional Maturity was held on June 1, 2017. As a result of this review, the PS-PVR panel recommended that the ABI L1b and CMI data be promoted to Provisional Validation Maturity as of June 1, 2017.

The ABI L1b data products are calibrated and geo-located radiances of the 16 ABI bands over the Full Disk (FD) of the Earth, the Continental United States (CONUS) region, the Mesoscale (MESO) regions, and certain instrument calibration and engineer data. Provisional maturity, by definition, means that:

  • Validation activities are ongoing and the general research community is now encouraged to participate.
  • Severe algorithm anomalies are identified and under analysis. Solutions to anomalies are in development and testing.
  • Incremental product improvements may still be occurring.
  • Product performance has been demonstrated through analysis of a small number of independent measurements obtained from select locations, periods, and associated ground truth or field campaign efforts.
  • Product analysis is sufficient to communicate product performance to users relative to expectations (performance baseline).
  • Documentation of product performance exists that includes recommended remediation strategies for all anomalies and weaknesses. Any algorithm changes associated with severe anomalies have been documented, implemented, tested, and share with the user community.
  • Testing has been fully documented.
  • Product is ready for operational use and for use in comprehensive cal/val activities and product optimization.

For more information about GOES-R product maturity levels, see the table at the end of this readme statement.

Users of Provisional data bear responsibility for inspecting the data prior to use and for the manner in which the data are utilized. Persons desiring to use the GOES-16 ABI Provisional maturity L1b and CMI products for any reason, including but not limited to scientific and technical investigations, are encouraged to consult the NOAA ABI cal/val scientists for feasibility of the planned applications (contact details below).

Known issues of ABI L1b radiances include:

  1. Navigation may have large errors.
  2. Channel-to-channel registration error does not always meet the requirement, especially between channels from the three groups of channels (1-6, 7-11, and 12-16 – they are in three different “focal plane assemblies” or FPA). For example, co-registration between Channel 2 and Channel 1 (same FPA) is often better than that between Channel 2 and Channel 7 (different FPA).
  3. Frame-to-frame registration may be unstable, causing features to “jump” in animation.
  4. Image striping is widespread for many channels and can be significant.
  5. Channel 2 may be ~7% brighter than commonly accepted values.
  6. The infrared (IR) measurements for the Continental United States (CONUS) and mesoscale (MESO) sections that are part of ABI Scan Mode 3 observations suffer “Periodic IR Calibration Anomaly” (PICA). These measurements demonstrate an artificial periodicity of 15 minutes. PICA seems uniformly small in terms of radiance, but can exceed 1K in terms of brightness temperature for cold scenes. PICA may affect some channel more than others, and during some hours of the day than others.
  7. Excessive stray light exists for VNIR channels approximately one hour before and after satellite local midnight for approximately forty days during the eclipse season before the vernal (spring) equinox and after the autumnal (fall) equinox, and may exist in other days of the year.
  8. Residual stray light exists for Channel 7 approximately one hour before and after satellite local midnight for approximately forty days during the eclipse season before the vernal (spring) equinox and after the autumnal (fall) equinox. These stray lights may affect certain applications even though they meet the requirement.
  9. VNIR channel calibration may have frequent but minor discontinuity following each solar calibration.
  10. The IR measurements may have small discontinuity twice a day around satellite noon and midnight. The effect should be so small for all channels that users should not be able to detect it, but please contact us if you do.

For CMI, all the issues noted above for the radiances are valid, in addition to the following:

  1. The maximum reflectance value is currently capped at 1.0. This will increase with a later software build.
  2. The multiband files don’t have the correct downscaling method listed in the metadata.
  3. The kappa0 value reported in the product is inconsistent with the correct kappa0 value applied to the reflectance factors.
  4. There are inconsistent data quality flag (DQF) values for off-Earth pixels.
  5. On occasion, the start time of a single band file is different from the other bands by 0.1 second.

ABI L1b CWG Team Lead: Fred Wu

ABI CMI AWG Team Lead: Tim Schmit

Below is a description of the GOES-R Product (L1b and L2+) Maturity Levels.

GOES-R Product (L1b and L2+) Validation Maturity Stages (Nominal Mission)

1. Beta

Preparation Activities
  • Initial calibration applied. (L1b)
  • Rapid changes in product input tables, and possibly product algorithms, can be expected.
  • Product quick looks and initial comparisons with ground truth data (if any) are not adequate to determine product quality.
  • Anomalies may be found in the product and the resolution strategy may not exist.
End state
  • Product are made available to the users to gain familiarity with data formats and parameters
  • Product has been minimally validated, and may still contain significant errors.
  • Product is not optimized for operational use.

2. Provisional

Preparation Activities
  • Validation and quality assurance (QA) activities are ongoing, and the general research community is now encourage to participate.
  • Severe algorithm anomalies are identified and under analysis. Solutions to anomalies are in development and testing.
  • Incremental improvements may be occurring.
  • Users are engaged in the Customer Forums (L2+ products only), and user feedback is assessed.
End state
  • Product performance (L1b or L2+) has been demonstrated through analysis of a small number of independent measurements obtained from selected locations, periods, and ground-truth/field program efforts.
  • Product analyses are sufficient to communicate product performance to users relative to expectations.
  • Documentation of product performance exists that includes recommended remediation strategies for all anomalies and weaknesses. Any algorithm changes associated with severe anomalies have been documented, implemented, tested, and shared with the user community.
  • Product is recommended for operational use and for use in comprehensive calibration/validation activities and product optimization.

3. Full

Preparation Activities
  • Validation, QA, and anomaly resolution activities are ongoing.
  • Incremental product improvements may still be occurring.
  • Users are engaged and user feedback is assessed.
End state
  • Product performance for all products is defined and documented over a wide range of representative conditions via ongoing ground-truth and validation efforts.
  • Products are operationally optimized, as necessary, considering mission parameters of cost and schedule, and technical competence is compared to user expectations.
  • All know product anomalies are documented and shared with the user community.
  • Product is operational.