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February 2018

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: 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 Thank you for your interest in NOAA CoastWatch.

September 2017

GOES-16 and Himawari-8 L2P SST are now available

NOAA CoastWatch/OceanWatch is now distributing GOES-16 SST (GHRSST L2P) and Himawari-8 SST (L2P). The data are updated once per hour with a two-week rotating buffer.

Click here to access the GOES 16 data:

Click here to access the Himawari-8 data:

Please remember that legacy GOES-13 SST will be discontinued. See news item below for further information.

September 2017

GOES-16 will replace GOES-13 in November 2017

NOAA CoastWatch/OceanWatch SST products will transition from GOES-13 data to GOES-16 data in November 2017. Please note that legacy GOES-13 SST products (gridded, in binary format) will be discontinued. 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.

Two GOES-16 products will be offered during the initial transition:

•  Advanced Clear-Sky Processer for Oceans (ACSPO) L2P full-disk GHRSST GDS 2.0. This product will be offered in NetCDF4 format at a one hour frequency with data sets of ~260 MB/hour or ~6.3 GB/day.

•  ACSPO L3U gridded GHRSST GDS 2.0. This product will be offered in NetCDF4 format at a 0.02 degree grid spacing (~2 km) with data sets of ~0.5 GB/day.

Please note that these products will have 8 hour x 5 day/week technical support (as opposed to 24 hour x 7day/week). Future updates (ACSPO v2.51/2.60) will include "collated" counterparts to L2P/L3U (L2C/L3C, respectively). The L2C/L3C products will use temporal consistency analyses and have improved coverage and better performance. To provide feedback on your GOES-16 SST data needs, please contact the CoastWatch/OceanWatch help desk at

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:

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:

Click here for more information about the AVHRR reanalysis:

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.

As of July 7, 2017 EUMETSAT OLCI Level 2 ocean color data products are released. Products are 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