4 km NODC/RSMAS AVHRR Pathfinder v5.0 7-day Data for 1996 (NODC Accession 0001791)

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The 4 km Pathfinder effort at the National Oceanic and Atmospheric Administration (NOAA) National Oceanographic Data Center (NODC) and the University of Miami's Rosenstiel School of Marine and Atmospheric Science (RSMAS) is an extension of and improvement on the sea surface temperature (SST) fields from the NOAA/NASA AVHRR Oceans 9km Pathfinder dataset. In this 4 km Pathfinder project, some important shortcomings in the original 9 km data have been corrected, and the entire time series has been reprocessed at the 4 km Global Area Coverage (GAC) level, the highest resolution possible globally.

Twice-daily SST and related parameters back to late 1981 have been produced, as well as temporal averages for 5-day, 7-day, 8-day, monthly, and yearly periods. This information is archived at the National Oceanographic Data Center.

This metadata record describes the temporally averaged 7-day SST data and related parameters available for 1996. Data for all other years and time periods are available as separate NODC accessions. The purpose of the NODC Pathfinder data is to provide sea surface temperature data and related parameters with good temporal consistency, high accuracy and spatial resolution, and for archive and distribution through the NOAA National Oceanographic Data Center (NODC). This SST data set is intended primarily for climate related applications and studies and is being established to help form the basis for a Climate Data Record for SST.
  • Cite as: Casey, Kenneth; US DOC/NOAA/NESDIS > National Oceanographic Data Center (2010). 4 km NODC/RSMAS AVHRR Pathfinder v5.0 7-day Data for 1996 (NODC Accession 0001791). Version 2.2. National Oceanographic Data Center, NOAA. Dataset. [access date]
gov.noaa.nodc:0001791
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Distribution Formats
  • Originator data format
Ordering Instructions Data may be searched and downloaded using online services provided by NCEI using the online resource URLs in this record. Contact NCEI Information Services for custom orders. When requesting data from NCEI, the desired data set may be referred to by the unique package identification number listed in this metadata record.
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 1996-01-01 to 1996-12-31
Spatial Bounding Box Coordinates
N: 90
S: -90
E: 180
W: -180
Spatial Coverage Map
General Documentation
Associated Resources
  • AVHRR Pathfinder version 5.0, interim version 5.0, and version 5.1 global 4km sea surface temperature (SST) data for 1981-2009
    • NCEI Collection
      Navigate directly to the URL for data access and direct download.
  • Parent ID (indicates this is related to other data):
    • gov.noaa.nodc:AVHRR_Pathfinder-NODC-v5.0_v5.1
Publication Dates
  • publication: 2010-12-13
  • revision: 2011-01-10
Edition 2.2
Data Presentation Form Digital table - digital representation of facts or figures systematically displayed, especially in columns
Dataset Progress Status Complete - production of the data has been completed
Data Update Frequency As needed
Supplemental Information
The Version 5.0 Pathfinder algorithm was used to
produce these twice-daily, 5-day, 7-day, 8-day, monthly, and yearly global SST and related
parameters (described below). This algorithm is an improved version of the previously most
successful of many methods used to derive SST from AVHRR observations (see Barton (1995)
for a review of earlier techniques), the University of Miami Pathfinder version v4.2 SST
algorithm (described fully in Kilpatrick et al., 2001).

The v4.2 algorithm offered marked improvement over operational retrieval
algorithms such as MCSST and was applied to AVHRR data to maximize accuracy and to
minimize artificial fluctuations arising from the sequence of AVHRR instruments flown on
NOAA's polar-orbiting satellites during the past 2 decades. The 9 km v4.2 Pathfinder SSTs have
already been shown to be the highest quality product currently available for the construction of
global climatologies (Casey and Cornillon, 1999) and longer-term SST trend determination
(Casey and Cornillon, 2001), and have been demonstrated to be accurate within about 0.3
degrees C under optimal conditions (Kearns et al., 2000). Relative to the older 9 km v4.2
Pathfinder data, the new, ~ 4 km resolution Pathfinder Version 5.0 global SSTs increase detail
roughly by a factor of four simply by virtue of the increased resolution. The increase in detail
over widely used but relatively coarse SST datasets such as Optimally Interpolated SST Version
2 (OISSTv2; Reynolds et al., 2002) and the Hadley Centre's Global Sea Ice and SST (HadISST1;
Rayner et al., 2003) is far greater.

In addition to the increased resolution, significant improvements have
been made in the Version 5.0 which enhance the usefulness of the SST fields. Currently, these
enhancements include the use of sea ice in the quality level determination scheme, inclusion of
many inland water bodies, and the use of a greatly improved land mask. The greatest
improvements are seen in coastal zones, marginal seas, and boundary current regions where SST
gradients are often large and their impact on operational or research products is greatest.
Separate SST products for daytime and nighttime AVHRR retrievals are made to better
understand the differences in skin and bulk temperatures, since mean differences between
AVHRR-measured skin temperatures and bulk temperatures of 0.1 to 0.2 degrees C (Schluessel
et al., 1990) and locally varying differences of up to 1.8 degrees C (Minnett et al., 2000) have
been observed.

In addition to SST values, the Pathfinder V5.0 Project makes six other
parameters available, for a total of seven per time step:
1. "All-pixel" SST - The all-pixel SST files contain values for each pixel
location, including those contaminated with clouds or other sources of error. The Overall Quality
Flag values may be used to filter out these unwanted values. The SST value in each pixel
location is an average of the highest quality AVHRR Global Area Coverage (GAC) observations
available in each roughly 4 km bin.
2. First-guess SST - The Pathfinder algorithm uses a first guess SST
provided by the Reynolds Optimally Interpolated SST Version 2 (OISSTv2) product. The
OISSTv2 is also used in the quality control procedures.
3. Number of observations - This parameter indicates the number of
AVHRR GAC observations falling in each approximately 4 km bin.
4. Standard deviation - This is the standard deviation of the observations in
each 4 km bin.
5. Overall quality flag - The overall quality flag is a relative assignment of
SST quality based on a hierarchical suite of tests. The Quality Flag varies from 0 to 7, with 0
being the lowest quality and 7 the highest. For more information regarding the suite of tests, see
the Kilpatrick et al. (2001) paper cited above.
6. Mask 1 - These files contain a mask code, which along with Mask 2,
can be used to determine the tests in the hierarchical suite that were passed or failed, resulting in
the Overall Quality Flag.
7. Mask 2 - These files contain a mask code, which along with Mask 1,
can be used to determine the tests in the hierarchical suite that were passed or failed, resulting in
the Overall Quality Flag.

This accession also includes a collection of value-added, cloud-screened products in HDF4. These products contain daytime, nighttime, and day-night averaged data of quality flags 4-7 only, as well as standard deviation and pixel count information. They have been produced from the original Pathfinder Version 5 data by NODC for Daily, 5-day, 7-day, and monthly temporal averages at 4km and one degree spatial resolution, as well as five degree spatial resolution for monthly products.

Note on Pathfinder Program: The Pathfinder program was jointly created
by NASA and NOAA through the Earth Observing System (EOS) Program Office in 1990. The
focus of the Pathfinder Program was to determine how existing satellite based data sets could be
processed and used to study global change. The data sets were designed to be long time-series
data processed with stable calibration and community consensus algorithms to better assist the
research community. For more information, see: National Aeronautics and Space Administration
(NASA). 1993. Earth Observing System (EOS) Reference Handbook, ed. G. Asrar and D. J.
Dokken. Washington, D. C.: National Aeronautics and Space Administration, Earth Science
Support Office, Document Resource Facility. The 4 km Pathfinder Project effort at the National
Oceanic and Atmospheric Administration (NOAA) National Oceanographic Data Center
(NODC) and the University of Miami's Rosenstiel School of Marine and Atmospheric Science
(RSMAS) is an extension of and improvement on the sea surface temperature (SST) fields from
that original NOAA/NASA AVHRR Oceans Pathfinder program.

In this accession, NODC has archived multiple versions of these data. The latest (and best) version of these data has the largest version number.
Purpose Basic research
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 data it distributes are an authentic copy of the records that were accepted for inclusion in the NCEI archives.
Theme keywords NODC DATA TYPES THESAURUS NODC OBSERVATION TYPES THESAURUS WMO_CategoryCode
  • oceanography
Global Change Master Directory (GCMD) Science and Services Keywords
  • EARTH SCIENCE > OCEANS > OCEAN TEMPERATURE > SEA SURFACE TEMPERATURE
Data Center keywords Global Change Master Directory (GCMD) Data Center Keywords
  • DOC/NOAA/NESDIS/NODC > National Oceanographic Data Center, NESDIS, NOAA, U.S. Department of Commerce
  • DOC/NOAA/NESDIS/NCEI > National Centers for Environmental Information, NESDIS, NOAA, U.S. Department of Commerce
  • DOC/NOAA/NESDIS/NODC > National Oceanographic Data Center, NESDIS, NOAA, U.S. Department of Commerce
NODC COLLECTING INSTITUTION NAMES THESAURUS NODC SUBMITTING INSTITUTION NAMES THESAURUS
Platform keywords NODC PLATFORM NAMES THESAURUS Global Change Master Directory (GCMD) Platform Keywords
  • NOAA-11 > National Oceanic & Atmospheric Administration-11
  • NOAA-14 > National Oceanic & Atmospheric Administration-14
  • NOAA-16 > National Oceanic & Atmospheric Administration-16
  • NOAA-9 > National Oceanic & Atmospheric Administration-9
Instrument keywords NODC INSTRUMENT TYPES THESAURUS Global Change Master Directory (GCMD) Instrument Keywords
  • AVHRR-2 > Advanced Very High Resolution Radiometer-2
  • AVHRR-3 > Advanced Very High Resolution Radiometer-3
Place keywords NODC SEA AREA NAMES THESAURUS Global Change Master Directory (GCMD) Location Keywords
  • GEOGRAPHIC REGION > GLOBAL OCEAN
Project keywords NODC PROJECT NAMES THESAURUS Global Change Master Directory (GCMD) Project Keywords
  • NOAA/NASA PATHFINDER > NOAA/NASA Pathfinder Program
Keywords NCEI ACCESSION NUMBER
Use Constraints
  • Cite as: Casey, Kenneth; US DOC/NOAA/NESDIS > National Oceanographic Data Center (2010). 4 km NODC/RSMAS AVHRR Pathfinder v5.0 7-day Data for 1996 (NODC Accession 0001791). Version 2.2. National Oceanographic Data Center, NOAA. Dataset. [access date]
Access Constraints
  • 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
  • Digital data may be downloaded from NCEI at no charge in most cases. For custom orders of digital data or to obtain a copy of analog materials, please contact NCEI Information Services for information about current fees.
Lineage information for: dataset
Processing Steps
  • 2010-12-13T22:44:54 - NCEI Accession 0001791 v1.1 was published.
  • 2011-01-10T22:46:33 - NCEI Accession 0001791 was revised and v2.2 was published.
    Rationale: Updates were received for this data set. These updates were copied into the data/0-data/ directory of this accession. These updates may provide additional files or replace obsolete files. This version contains the most complete and up-to-date representation of this archival information package. All of the files received prior to this update are available in the preceding version of this accession.
Output Datasets
Lineage information for: repository
Processing Steps
  • 2015-04-22T00:00:00 - NOAA created the National Centers for Environmental Information (NCEI) by merging NOAA's National Climatic Data Center (NCDC), National Geophysical Data Center (NGDC), and National Oceanographic Data Center (NODC), including the National Coastal Data Development Center (NCDDC), per the Consolidated and Further Continuing Appropriations Act, 2015, Public Law 113-235. NCEI launched publicly on April 22, 2015.
Acquisition Information (collection)
Instrument
  • AVHRR-2
  • AVHRR-3
Platform
  • NOAA-11
  • NOAA-14
  • NOAA-16
  • NOAA-9
Last Modified: 2018-08-08T21:57:08
For questions about the information on this page, please email: NODC.DataOfficer@noaa.gov