Users of VIIRS ocean color products should be aware of a processing anomaly that affected products for the days of 16 and 17 January 2020.  The source of the problem in the satellite data records (SDR; i.e., Level 1) has been resolved as of 18 January production.  CoastWatch will be assessing impacts on CoastWatch products (environmental data records EDR or Level 2; and higher level processing, Level 3, Level 4) for this period.   Some data files may be flagged or removed.  Please consider potential impacts to your applications if you have routinely ingested VIIRS near real time ocean color files during this time period.  Also, be aware of any temporal composite applications covering this time.  Contact the helpdesk if you have specific concerns or questions.

The official outage and updates text from the NOAA Environmental Satellite Processing Center (ESPC) is included below.  Note, CoastWatch does not serve any OMPS or CrIS sensor data.

------------------------------

Update #3: OMPS products have checked out as nominal.  All NOAA-20 and S-NPP VIIRS SDR reflective solar bands (RSB), OMPS SDR and EDRs and CrIS SWIR bands are nominal as of the reported time of Jan 17, 2020 at 22:11Z.  

Update #2:  On Jan 17, 2020 at 22:11Z a fix was implemented to a general science module/library that impacted processing of NOAA-20 and S-NPP VIIRS SDR reflective solar bands (RSB), OMPS SDR and EDRs and CrIS SWIR band at day time.  All products except OMPS are back to meeting specification as of this update.  Investigation into OMPS failures, primarily on the NDE product generation system are still being investigated.  Another update will follow when OMPS products are returned back to nominal.

Update #1: A fix has been identified and is in the process of being deployed within the next several hours.  Users should expect varying levels of degradation in both the SDR and EDR products until the fix is fully implemented.  Please see updated information below.

Original Report:

Topic: VIIRS SDR reflective solar bands (RSB), OMPS SDR and EDRs and CrIS SWIR band at day time

Date/Time Issued:  January 17, 2020 2308Z

Product(s) or Data Impacted: VIIRS SDR reflectance/radiance products and L2+ products using RSB bands, OMPS SDR and EDRs, CrIS SWIR band at day time and L2+products 

Date/Time of Initial Impact: January 16, 2020 0000Z

Date/Time of Expected End: TBD (no later than January 18, 2020 0000Z)

Length of Event:  TBD

Details/Specifics of Change: 

There has been an anomaly in the VIIRS SDR reflective solar bands (RSB) calibration for both NOAA-20 and S-NPP due to an unexpected change in the solar vector since about 2020-01-16 0:00 UTC. As a result, large errors in VIIRS SDR reflectance/radiance products have been observed which affect RSB based products.  

This anomaly appears to affect the OMPS SDR as well with large errors in the Solar Zenith Angles.  As a result almost all V8TOz and V8Pro EDRs have very large errors in derived ozone and other estimates (only 20% of these bad values are flagged). EDRs have also been impacted as of 2020-01-16 0:00Z. The IDPS Team is working on the problem but the OMPS Nadir EDR products should not be used until further notice. 

The impact to CrIS should be only limited to CrIS Short Wave Infrared band at day time.

ESPC Level 2 products using VIIRS RSB bands and OMPS level 2 products are degraded. NESDIS is diligently investigating and working towards a solution.  Further updates will be provided as conditions change.

--------------------------------------