Dataset Overview | National Centers for Environmental Information (NCEI)

AVHRR Pathfinder version 5.0 and 5.1 global 4km sea surface temperature (SST) daily, 5-day, and monthly harmonic climatologies for 1982-2008

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This dataset contains global, 4km daily, 5-day, and monthly sea surface temperature climatologies derived from harmonic analysis of the AVHRR Pathfinder Version 5.0 and 5.1 sea surface temperature time series data for 1982-2008. The daily climatology is available as 366 separate files, each representing one day in a climatological year. The 5-day climatology is available as 73 separate files, each representing a 'pentad,' or 5-day period, in a climatological year. The monthly climatology is available as 12 separate files, each representing one month in a climatological year. The files are in netCDF-4 and fully comply with the GHRSST Data Specification 2.0 for Level 4 products. In addition to climatological sea surface temperature, each file contains standard deviation, sea ice concentration, sea ice concentration error, and land mask information.

This accession also includes 'classic', or mean, daily, 5-day, and monthly sea surface temperature climatologies derived from the same Pathfinder time series data. These climatologies were used to gap-fill the harmonic climatologies, and provided the standard deviation information.

In some ice-dominated high-latitude areas, the harmonic climatology is poorly constrained due to uneven distribution throughout the year of the valid measurements. For example, at 67.5S, 73W near the Antarctic coast, temperatures estimated in the harmonic climatology reach almost 40C. In these regions, the classic, averaged climatological values may be more reliable.
  • Cite as: Casey, Kenneth S.; Kearns, Edward J.; Halliwell, Vicki; Evans, Robert (2011). AVHRR Pathfinder version 5.0 and 5.1 global 4km sea surface temperature (SST) daily, 5-day, and monthly harmonic climatologies for 1982-2008. [indicate subset used]. NOAA National Centers for Environmental Information. Dataset. https://www.ncei.noaa.gov/archive/accession/AVHRR_Pathfinder-NODC-v5.0_v5.1-climatologies. Accessed [date].
  • Please refer to Credit tab for full citation information.
gov.noaa.nodc:AVHRR_Pathfinder-NODC-v5.0_v5.1-climatologies
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Distribution Formats
  • NetCDF (Version: 4.1.2 classic model)
  • HDF (Version: 20080214)
    • File Specification: NCSA Hierarchical Data Format (HDF 4), Scientific Data Set (HDF-SDS)
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Distributor NOAA National Centers for Environmental Information
NCEI.Info@noaa.gov
Dataset Point of Contact NOAA National Centers for Environmental Information
ncei.info@noaa.gov
Time Period 1982-01-01 to 2008-12-31
Spatial Bounding Box Coordinates
N: 90
S: -90
E: 180
W: -180
Spatial Coverage Map
General Documentation
Associated Resources
Publication Dates
  • publication: 2011-11-16
  • revision: 2011-12-17
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
Historical archive - data has been stored in an offline storage facility
Data Update Frequency As needed
Supplemental Information
The procedure used to generate these harmonic climatologies can be broken down into two primary components:

1. Harmonic analysis of time series data

Each harmonic climatology is created by fitting to a time series of SST data at each pixel a cosine function containing both annual and semi-annual components:

SST = A * cos(2pi*t + B) + C * cos(4pi*t + D) + E

The constants A and B correspond to the annual amplitude and annual phase, respectively. The constants C and D correspond to the semi-annual amplitude and phase. The constant E is the long term mean at that pixel.

The input time series consists of pentad (5-day) averages of best-quality data (quality flag 7) only for 1982-2008. These data have been archived by NODC in separate yearly accessions.

To create a gap-free dataset for analysis, median spatial fill routines are applied to each 5-day global SST average in the time series. Using a curve-fitting tool in Matlab (lsqcurvefit.m), the cosine function is fit to the SST time series and the five harmonic constants are calculated. Note: If fewer than 100 good observations are available for a given pixel, the amplitudes (A and C) are set to zero, phases (B and D) set to one, and the long term mean (E) is set to the mean at that pixel.

2. Application of harmonic parameters

The five harmonic constants can then be plugged into the cosine function to solve for sea surface temperature at any temporal resolution. The constants are applied at either daily, 5-day, and monthly resolution to calculate sea surface temperature for 366 days, 73 pentads, and 12 months, respectively, in a climatological year. Any remaining pixels with missing values after median filling are filled using SST values from the classic climatology.

File-naming convention for daily harmonic climatology files:

[0000][MMDD][HHMMSS]-NODC-L4_GHRSST-SSTskin-AVHRR_Pathfinder-PFV5.0_Daily_Climatology_1982_2008_DayNightCombined-v02.0-fv[##.#].nc

0000 - representative year of analysis (climatological year)
MMDD - representative month and day of analysis, e.g. 0630 for June 30 of the climatological year
HHMMSS - representative time (6-digit hour, minute and second) of analysis. All files use value "200000" to represent 8 PM, the midpoint of the approximate AVHRR "day" based on an average equator-crossing time of 2 PM.
##.# - file version, e.g. 01.0

File-naming convention for 5day harmonic climatology files:
[0000][MMDD][HHMMSS]-NODC-L4_GHRSST-SSTskin-AVHRR_Pathfinder-PFV5.0_5day_Climatology_1982_2008_DayNightCombined-v02.0-fv[##.#].nc

0000 - representative year of analysis (climatological year)
MMDD - representative month and day of analysis, e.g. 0630 for June 30 of the climatological year
HHMMSS - representative time (6-digit hour, minute and second) of analysis.
##.# - file version, e.g. 01.0

File-naming convention for monthly harmonic climatology files:
[0000][MMDD][HHMMSS]-NODC-L4_GHRSST-SSTskin-AVHRR_Pathfinder-PFV5.0_Monthly_Climatology_1982_2008_DayNightCombined-v02.0-fv[##.#].nc

0000 - representative year of analysis (climatological year)
MMDD - representative month and day of analysis, e.g. 0630 for June 30 of the climatological year
HHMMSS - representative time (6-digit hour, minute and second) of analysis.
##.# - file version, e.g. 01.0
Purpose To provide daily day-night combined climatologies of SST with high accuracy and high spatial resolution.
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: Casey, Kenneth S.; Kearns, Edward J.; Halliwell, Vicki; Evans, Robert (2011). AVHRR Pathfinder version 5.0 and 5.1 global 4km sea surface temperature (SST) daily, 5-day, and monthly harmonic climatologies for 1982-2008. [indicate subset used]. NOAA National Centers for Environmental Information. Dataset. https://www.ncei.noaa.gov/archive/accession/AVHRR_Pathfinder-NODC-v5.0_v5.1-climatologies. Accessed [date].
  • Please also cite: Casey, K.S., T.B. Brandon, P. Cornillon, and R. Evans (2010). "The Past, Present and Future of the AVHRR Pathfinder SST Program", in Oceanography from Space: Revisited, eds. V. Barale, J.F.R. Gower, and L. Alberotanza, Springer. https://doi.org/10.1007/978-90-481-8681-5_16
Cited Authors
Contributors
Resource Providers
Publishers
Theme keywords NODC DATA TYPES THESAURUS NODC OBSERVATION TYPES THESAURUS WMO_CategoryCode
  • oceanography
GHRSST Project Science Keywords
  • EARTH SCIENCE > Oceans > Ocean Temperature > Sea Surface Temperature > AVHRR
  • EARTH SCIENCE > Oceans > Ocean Temperature > Sea Surface Temperature > AVHRR > 4km Pathfinder
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 ICES/SeaDataNet Ship 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 Global Change Master Directory (GCMD) Project Keywords
Keywords NCEI ACCESSION NUMBER
Use Constraints
  • Cite as: Casey, Kenneth S.; Kearns, Edward J.; Halliwell, Vicki; Evans, Robert (2011). AVHRR Pathfinder version 5.0 and 5.1 global 4km sea surface temperature (SST) daily, 5-day, and monthly harmonic climatologies for 1982-2008. [indicate subset used]. NOAA National Centers for Environmental Information. Dataset. https://www.ncei.noaa.gov/archive/accession/AVHRR_Pathfinder-NODC-v5.0_v5.1-climatologies. Accessed [date].
  • Please also cite: Casey, K.S., T.B. Brandon, P. Cornillon, and R. Evans (2010). "The Past, Present and Future of the AVHRR Pathfinder SST Program", in Oceanography from Space: Revisited, eds. V. Barale, J.F.R. Gower, and L. Alberotanza, Springer. https://doi.org/10.1007/978-90-481-8681-5_16
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: series
Processing Steps
  • 2011-11-16T01:27:27Z - NCEI Accession 0071181 v1.1 was published.
  • 2011-11-21T17:26:08Z - NCEI Accession 0071182 v1.1 was published.
  • 2011-12-17T21:14:54Z - NCEI Accession 0075098 v1.1 was published.
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-17
  • NOAA-18
  • NOAA-7
  • NOAA-9
Last Modified: 2021-07-13T17:09:22Z
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