Recent degradation of the NASA Suomi-NPP SST product

Use this Forum to find information on, or ask a question about, NASA Earth Science data.
Post Reply
OB.DAAC - SeanBailey
User Services
User Services
Posts: 1464
Joined: Wed Sep 18, 2019 6:15 pm America/New_York
Answers: 1
Been thanked: 5 times

Recent degradation of the NASA Suomi-NPP SST product

by OB.DAAC - SeanBailey » Tue Feb 19, 2019 12:14 pm America/New_York

It has recently become apparent that the characteristics of the Suomi-NPP NASA SST products (R2016.0) underwent a significant change in mid September 2018. 
At that time, the OBPG updated forward processing to use a new version (v3.0) of the VIIRS Level-1 processing software. 
This version outputs the M13 band (4-micron) as a 32 bit integer. 
Previously the product was stored as a 16 bit integer.  
A corresponding change was not made to the Level 2 processing code,resulting in an erroneous treatment of the M13 band. 
This band is used in the derivation of the product flagging for both the triple window SST and the standard 11-micron SST product. 
The impact of this is most evident at Level 3, or in products that use this quality information (e.g. the VIIRS-SNPP GHRSST distributed by the PO.DAAC)
Users who have downloaded any of the affected VIIRS-SNPP SST products are advised to exercise caution in using these products data for any application.
Both the OB.DAAC and the PO.DAAC have removed the affected products from distribution. 
The OBPG is in the process of regenerating these products with corrected code. 
It is recommended that users re-acquire these products once they have been regenerated.

A related note to the community:
As a result of a funding decision, NASA VIIRS SST’s have become “orphaned”unsupported products and are not monitored to the extent they were before.
Previously, the SST group at the Rosenstiel School of Marine and Atmospheric Science at the University of Miami were responsible for the validation, accuracy assessment, and product quality, but ceased to be funded for VIIRS in summer 2018. No other group was funded to maintain or validate the VIIRS SSTs.
Any questions or technical concerns should be directed to the appropriate contacts at the OB.DAAC and the PO.DAAC.

UPDATE (21 Feb 2019):The OBPG has competed the reprocessing of the affected data

Tags:

Post Reply