February 2018 - VIIRS Quality Issue

Data Quality NOTICE: Near Real Time VIIRS SNPP Ocean Color products are severely degraded from 16 February 2018 until further notice.

Dear Users,

Due to a calibration issue affecting the NOAA/IDPS Sensor Data Record (SDR, i.e., L1B) for VIIRS SNPP, the Near Real Time Ocean Color Environmental Data Record (EDR) products from 16 February 2018 until further notice are severely degraded. The VIIRS Ocean Color Science Team (EDR data producer) suggests products "should not be used." The NOAA/JPSS SDR team is investigating the problem. This notice includes NOAA MSL12 Near Real Time products available through CoastWatch as well as through OSPO because both are processed from NOAA/IDPS SDR. We will advise when data quality is restored.

Note that the NOAA MSL12 Science Quality (15 day delayed mode) Ocean Color EDR products are not affected by this current issue and will be usable as they come online at CoastWatch in a few days. Also, merged and mapped Level 3 Ocean Color products generated at CoastWatch from the Science Quality data will be unaffected.

Please contact the CoastWatch help desk if you have questions. Thank you for using NOAA CoastWatch/OceanWatch data.

February 2018 - Data format change

Changes for Near Real-time VIIRS Ocean Color Products

The S-NPP VIIRS ocean color products produced within NOAA STAR are undergoing a processing change (products produced in near real-time operationally within OSPO will remain unchanged). As a result, beginning February 20, 2018 the following changes are expected:

  • Improvements in data due to the update of the NOAA MSL12 processing (Level-2 / Level-3)
  • Changes in naming convention (Level-2)
  • Change in NetCDF structure (Level-2)
  • Change in location of data on CoastWatch servers (Level-2)
  • Change in retention of data to 1 year (Level-2 and Level-3 merges)

The CoastWatch VIIRS near-real-time ocean color Level-2 and Level-3 products will be produced from MSL12 v1.2x. The Algorithm Theoretical Basis Document (Wang, et al., 2017) details all processing and products for MSL12 v1.2x. In addition to processing updates, changes to products include:

  • New quality product: QA Score and I-band
  • Wavelength indication changed to nominal center-wavelength for VIIRS-SNPP normalized water-leaving radiances (nLw(λ))
  • NetCDF metadata changes for compatibility with CW
  • L2 flag changes (see ATBD for list)
  • High resolution 250 m landmask

Standard VIIRS SNPP ocean color data Level-2 products from MSL12 v1.2x (both near-real-time and science quality) include:

  • Normalized water-leaving (nLw(λ)) at 6 the VIIRS six visible bands (nominal center wavelengths)
  • M1 (410 nm)
  • M2 (443 nm)
  • M3 (486 nm)
  • M4 (551 nm)
  • M5 (671 nm)
  • I1 (638 nm)
  • Chlorophyll-a concentration
  • Diffuse attenuation coefficient at 490 nm (Kd(490)), and
  • Diffuse attenuation coefficient of photosynthetically available radiation (Kd(PAR))
  • QA Score (a quantitative assessment of VIIRS ocean color performance with respect to an empirical catalog of in situ spectra,see Wei et al., 2016.)

Wang, M., X. Liu, L. Jiang and S. Son, "The VIIRS Ocean Color Products", Algorithm Theoretical Basis Document Version 1.0, 68 pp., June 2017.

Wei, J., Z. Lee, and S. Shang (2016), A system to measure the data quality of spectral remote-sensing reflectance of aquatic environments, J. Geophys. Res. Oceans, 121, 81898207, doi:10.1002/2016JC012126. (non-government website)

In addition to the data quality improvements, near real-time products will share a similar naming convention to the science quality data processed for S-NPP VIIRS:

Level-2 ocean color products are organized by Year and Day-of-the-Year. Filenames will appear as follows: V2018037003435_NPP_NRTNIR_L2.nc where:

  • V: Sensor VIIRS
  • 2017: Year of observation (YYYY)
  • 037: Day of year for the observation (DDD)
  • 003435: Hour, minutes, and seconds of the start of observation (hhmmss) in UTC
  • NPP: Spacecraft S-NPP
  • [NRT,SCI]NIR: Sensor data record source and environmental data record algorithm. Indicates Near Real-time or Science Quality output for distribution
  • L2: Processing level. L2 includes calibrated and geolocated geophysical products

Data files are in NetCDF4/CF but differ from past NOAA CoastWatch near real-time ocean color products in their use of hierarchical groups to store attributes, variables, variable naming, and dimensions. CoastWatch Utilities Software has been updated to work with these files. Additional metadata can be obtained using THREDDS services such as ISO or OPeNDAP to view the contents of a selected file.

These files will be available through the CoastWatch THREDDS server at the following URL:


Our website will be updated to reflect these new files. If you have questions, please submit them to coastwatch.info@noaa.gov. Thank you for your interest in NOAA CoastWatch.

September 2017

GOES-16 will replace GOES-13 as GOES East in November 2017

Users of geo-SST products,

This notice is to inform you and your group that certain legacy geo-SST products will be discontinued or severely impacted with the transition of GOES-13 to GOES-16 on or about November 20, 2017.

The legacy GOES-13 SST products, (gridded, in binary format) were not planned for continuation for GOES-16.

NESDIS STAR has two products that are planned for GOES-16 and we are planning to provide these products via the Product Distribution and Access (PDA) platform in OSPO and via an ftp server in STAR. These products will initially only be supported no an 8X5 basis so users need to be aware of that limitation.

The two products that will be offered initially are the Advanced Clear-Sky Processor for Oceans (ACSPO) level 2P full-disk GHRSST GDS 2.0 netcdf4 product. We will initially offer this at one per hour frequency as these data sets are very large (~260MB each for a total of 6.3GB/day). The second product will be an ACSPO gridded GHRSST GDS 2.0 L3U product (netcdf4) at 0.02 degree grid spacing (roughly 2km). This data set will be much smaller (roughly 0.5GB/day for 24 hourly files) and more network friendly. Users are urged to please provide us feedback as to your GOES-16 SST data needs, if you need data more frequently than one data set per hour, or if you have ideas or needs for other types of SST products from GOES-16 (such as the 3-hourly or the daily products). The L3U data should be available toward the end of September.

The NOAA STAR CoastWatch ftp server now has a 2-week rotating buffer (reported once per hour) of the GHRSST L2P GOES-16 SST (as well as the Himawari-8 SST L2P) data for your exploration. ftp://ftp.star.nesdis.noaa.gov/pub/socd4/coastwatch/sst/nrt/

The /abi directory has the GOES-16 data and the /ahi directory has the Himawari-8 data

Future work (ACSPO v2.51/2.60) will be creating "collated" counterparts to L2P/L3U (L2C/L3C, respectively), which will be organized exactly the same way as the current L2P/L3U, but created using "temporal consistency analyses", and having better coverage (due to using intermediate 10/15min data to draw an upper-envelope to the diurnal cycle) and better performance (due to reduced residual cloud and suppressed noise)

We apologize for any inconvenience or disruptions that this discontinuation may cause but we are looking forward to a new era of high quality GOES-SST products in a more standard format which are monitored closely for quality and consistency. Monitoring/validation of these data will be done in the NOAA SQUAM and ARMS systems. Contact Sasha Ignatov Alex.Ignatov@noaa.gov with questions regarding validation.

July 2017


Dear CoastWatch VIIRS Ocean Color User,

Good news! The NOAA VIIRS Science Quality Ocean Color Level 2 Environmental Data Record products have been improved. Currently, CoastWatch is replacing the entire mission-long dataset with the new dataset from MSL12 v1.21 reprocessing. The new dataset will be available August 9,2017. Please check back soon to access full mission, MLS12 v1.21 VIIRS ocean color products.

Thanks for your interest in CoastWatch data. Please consider signing up for our mailing list for future announcements.

Level-2 and Level-3 OLCI datasets are now available.

NOAA CoastWatch/OceanWatch is now distributing Sentinel-3 OLCI Level-2 and Level-3 ocean color datasets. Data is provided courtesy of EUMETSAT as part of the Copernicus Program. NOAA CoastWatch will be increasing product coverage over the next month.

For more information, please refer to our OLCI near real-time product page.

Level-3 daily sea level anomaly datasets are now available.

NOAA CoastWatch/OceanWatch is now distributing daily Level-3 sea level anomaly datasets produced by the NOAA Laboratory for Satellite Altimetry. The datasets are produced globally with near-real time data from a constellation of radar altimeter missions.

Click here for more information: https://coastwatch.noaa.gov/cw_html/SSH_SeaLevelAnomaly.html

Reanalysis products for ACSPO SST are now available for VIIRS (Level-2P and Level-3U) and AVHRR (Level-2P).

Sea Surface Temperature products for VIIRS and AVHRR have been reanalyzed by NOAA’s Advanced Clear-Sky Processor for Oceans (ACSPO) using NOAA’s enterprise algorithm.

The VIIRS reanalysis is available at Level-2P and Level-3U and the AVHRR is reanalysis is available at Level-2P.

Click here for more information about the VIIRS reanalysis: https://coastwatch.noaa.gov/cw_html/SeaSurfaceTemp_ScienceQuality_VIIRS_SNPP.html

Click here for more information about the AVHRR reanalysis: https://coastwatch.noaa.gov/cw_html/SeaSurfaceTemp_ScienceQuality_AVHRR.html

March 2017

Level-1B OLCI-Sentinel-3A data now available.

NOAA CoastWatch/OceanWatch is currently distributing near-real time Level-1B full resolution global ocean data from OLCI-Sentinel-3A Copernicus mission in support of operational oceanography.

True color image
True color image produced today (15 February 2017) by NOAA CoastWatch/OceanWatch from OLCI-Sentinel-3A data.

Upon formal release by EUMETSAT, OLCI Level 2 ocean color data products also will be available through CoastWatch/OceanWatch. In accordance with a Technical Arrangement with EUMETSAT, NOAA is the primary provider of Sentinel-3 marine data for the US. OLCI data can be accessed through CoastWatch/OceanWatch using the granule selector tool.

From this tool, users can select granules of regions and dates of interest and view and download PNG true color images or download data files in either EUMETSAT TAR or CoastWatch HDF data formats. Multiple files can be downloaded at one time by selecting each granule of interest and clicking the "+" to add file names to the data cart, then automatically generate a list of those files to use in a download script (e.g., wget, etc.).

Granule Selector Tool
Screen shot of granule selector tool with data cart populated with 4 files.

June 2016

S-NPP VIIRS Life-of-Mission Science Quality Level-2 Ocean Color products are available.

Click here for more information: VIIRS Science Quality L2 Skip Navigation

February 2016

Version 3.3.2 of the CoastWatch Utilities CoastWatch Data Analysis Tool (CDAT) is now available.

Click here for more information: Software & Utilities