Dataset Overview | National Centers for Environmental Information (NCEI)

NOAA AVHRR Clear-Sky Products over Oceans (ACSPO): Sea Surface Temperature, Clear Sky Radiances, and Aerosol Optical Depth for the Global Ocean, 2011 - present (NCEI Accession 0072979)

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Advanced Clear Sky Processor over Oceans (ACSPO) - generates Sea Surface Temperature product files from multiple platforms and sensors. The products are from the AVHRR instrument aboard the older POES series of spacecrafts, as well as from the European Metop mission. Beginning on October 14, 2017, the ASCPO data changed formats from HDF4 to NetCDF4 to adhere to the Group for High Resolution SST (GHRSST) GDS2 data specification. Two spatial resolutions had been provided, 4 km from GAC data and 1 km from the Metop FRAC data.

Other parameters that can be found in the product files can include (dependent on date and product type) satellite and solar geometry (solar and satellite zenith angles and relative azimuth angles), thermal band brightness temperatures, visible band albedos, and bit flags indicating viewing conditions such as cloud, day/night, sun glint, etc. Also included in the current GHRSST files are an SST quality indicator, delta SST compared to a reference SST from a current SST analysis from an independent source, numerical weather model forecast u and v wind, as well as single sensor error statistics (SSES) (bias and standard deviation) at each pixel.
  • Cite as: Lillibridge, John; Office of Satellite Data Processing and Distribution (2020). NOAA AVHRR Clear-Sky Products over Oceans (ACSPO): Sea Surface Temperature, Clear Sky Radiances, and Aerosol Optical Depth for the Global Ocean, 2011 - present (NCEI Accession 0072979). [indicate subset used]. NOAA National Centers for Environmental Information. Dataset. https://accession.nodc.noaa.gov/0072979. Accessed [date].
gov.noaa.nodc:0072979
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Distribution Formats
  • HDF (Version: 4)
    • File Specification: NCSA Hierarchical Data Format (HDF 4), Scientific Data Set (HDF-SDS)
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Distributor DOC/NOAA/NESDIS/NCEI > National Centers for Environmental Information, NESDIS, NOAA, U.S. Department of Commerce
301-713-3277
NCEI.Info@noaa.gov
Dataset Point of Contact Information Services
DOC/NOAA/NESDIS/NCEI > National Centers for Environmental Information, NESDIS, NOAA, U.S. Department of Commerce
301-713-3277
NCEI.Info@noaa.gov
Time Period 2011-07-01 to Present
Spatial Reference System urn:ogc:def:crs:EPSG:4326
Spatial Bounding Box Coordinates
N: 90
S: -90
E: 180
W: -180
Spatial Coverage Map
General Documentation
Associated Resources
  • NOAA AVHRR Clear-Sky Products over Oceans (ACSPO): Sea Surface Temperature, Clear Sky Radiances, and Aerosol Optical Depth for the Global Ocean, 2011 - present
    • NCEI Collection
      Navigate directly to the URL for data access and direct download.
  • Advanced Clear Sky Processor for Ocean (ACSPO)
  • AVHRR Clear-Sky Processor for Oceans (ACSPO) Interface Control Document
  • Implementation of the Community Radiative Transfer Model in Advanced Clear-Sky Processor for Oceans and validation against nighttime AVHRR radiances
  • Parent ID (indicates this dataset is related to other data):
    • gov.noaa.nodc:NOAA-ACSPO-SST
Publication Dates
  • publication: 2020-04-23
Data Presentation Form Digital table - digital representation of facts or figures systematically displayed, especially in columns
Dataset Progress Status Ongoing - data is continually being updated
Historical archive - data has been stored in an offline storage facility
Data Update Frequency As needed
Purpose The purpose of the AVHRR Clear-Sky Processor over Oceans is to produce clear-sky products over oceans from the Advanced Very High Resolution Radiometer (AVHRR) for the designated user community.
Use Limitations
  • accessLevel: Public
  • Distribution liability: NOAA and NCEI make no warranty, expressed or implied, regarding these data, nor does the fact of distribution constitute such a warranty. NOAA and NCEI cannot assume liability for any damages caused by any errors or omissions in these data. If appropriate, NCEI can only certify that the data it distributes are an authentic copy of the records that were accepted for inclusion in the NCEI archives.
Dataset Citation
  • Cite as: Lillibridge, John; Office of Satellite Data Processing and Distribution (2020). NOAA AVHRR Clear-Sky Products over Oceans (ACSPO): Sea Surface Temperature, Clear Sky Radiances, and Aerosol Optical Depth for the Global Ocean, 2011 - present (NCEI Accession 0072979). [indicate subset used]. NOAA National Centers for Environmental Information. Dataset. https://accession.nodc.noaa.gov/0072979. Accessed [date].
Cited Authors
Contributors
Resource Providers
Points of Contact
  • John F. Sapper
    US DOC; NOAA; NESDIS; Office of Satellite and Product Operations (OSPO)
Publishers
Acknowledgments
  • NOAA STAR and NOAA OSDPD
Theme keywords NODC DATA TYPES THESAURUS NODC OBSERVATION TYPES THESAURUS WMO_CategoryCode
  • oceanography
Global Change Master Directory (GCMD) Science Keywords
Data Center keywords Global Change Master Directory (GCMD) Data Center Keywords NODC COLLECTING INSTITUTION NAMES THESAURUS NODC SUBMITTING INSTITUTION NAMES THESAURUS
Platform keywords NODC PLATFORM NAMES THESAURUS Global Change Master Directory (GCMD) Platform Keywords SeaDataNet Ship and Platform Codes
Instrument keywords NODC INSTRUMENT TYPES THESAURUS Global Change Master Directory (GCMD) Instrument Keywords
Place keywords NODC SEA AREA NAMES THESAURUS Global Change Master Directory (GCMD) Location Keywords
Project keywords NODC PROJECT NAMES THESAURUS
Keywords NCEI ACCESSION NUMBER
Use Constraints
  • Cite as: Lillibridge, John; Office of Satellite Data Processing and Distribution (2020). NOAA AVHRR Clear-Sky Products over Oceans (ACSPO): Sea Surface Temperature, Clear Sky Radiances, and Aerosol Optical Depth for the Global Ocean, 2011 - present (NCEI Accession 0072979). [indicate subset used]. NOAA National Centers for Environmental Information. Dataset. https://accession.nodc.noaa.gov/0072979. Accessed [date].
Access Constraints
  • Use liability: NOAA and NCEI cannot provide any warranty as to the accuracy, reliability, or completeness of furnished data. Users assume responsibility to determine the usability of these data. The user is responsible for the results of any application of this data for other than its intended purpose.
Fees
  • In most cases, electronic downloads of the data are free. However, fees may apply for custom orders, data certifications, copies of analog materials, and data distribution on physical media.
Lineage information for: dataset
Processing Steps
  • 2020-04-23T20:26:32Z - NCEI Accession 0072979 v1.1 was published.
Output Datasets
Lineage information for: dataset
Processor
  • DOC/NOAA/NESDIS/STAR > Center for Satellite Applications and Research, NESDIS, NOAA, U.S. Department of Commerce
Processing Steps
  • The application is data-driven from all AVHRR GAC and FRAC Level 1b data. HRPT and LAC data are also processed. The ACSPO Orbital Processor (OP) computes albedos and brightness temperatures at all pixels from calibration coefficients. A cloud detection algorithm determines clear pixels. Regression sea surface temperature and single-channel aerosol optical depth are computed at all pixels that are determined, using a land mask, to be over water. The clear-sky mask available in ACSPO is provided to identify clear-sky pixels, which define the domain of the ACSPO products. The ACSPO OP simulates clear-sky brightness temperatures (BT) with the Community Radiative Transfer Model (CRTM). These parameters are calculated on the NCEP 1 degree grid using NCEP GFS and Reynolds 1 degree weekly (v2) SST, and then bilinearly interpolated to every AVHRR pixel. These are currently used to improve the clear-sky mask in ACSPO and to perform quality control of AVHRR clear-sky radiances over ocean. In the near future, physical SST retrievals will be implemented. The predecessor of the ACSPO OP is the Clouds from AVHRR Extended (CLAVR-x) software. The structure of the AVHRR algorithm file used by the ACSPO OP has been inherited from CLAVR-x. The AVHRR algorithm file contains the instrument-specific parameters in standard algorithms that have been adopted into the CLAVR-x system. The ACSPO OP algorithm file contains daytime and nighttime operational SST coefficients, but does not use ice and land coefficients inherited from CLAVR-x. To allow quick cross-evaluation of ACSPO SST against the NESDIS heritage Main Unit Task (MUT) SST product, the ACSPO OP is initially set to use the same SST coefficients as the MUT system (calculated from heritage buoy match files). GAC granules will be created hourly and FRAC granules will be created every 10 minutes.
Acquisition Information (collection)
Instrument
  • AVHRR-3
Platform
  • MetOp-A
  • NOAA-17
  • NOAA-18
  • NOAA-19
Last Modified: 2020-04-23T21:29:36Z
For questions about the information on this page, please email: NODC.DataOfficer@noaa.gov