Source/sensor: NOAA Advanced Very-High-Resolution Radiometer (AVHRR)

Coverage by algorithm:

Version 5: 1985-Current
Interim Version 4.1: 2000-2003
Version 4.1: 1985- 1999

Abstract: Version 5.0 of the NODC/RSMAS AVHRR Oceans Pathfinder SST data set has significant improvements over previous versions, including 4.1. This data set is being distributed in collaboration with the National Oceanographic Data Center and the University of Miami's Rosenstiel School of Marine and Atmospheric Sciences. A complete collection of this data may be obtained through the NODC web site at: http://pathfinder.nodc.noaa.gov. Additionally data may be accessed through their FTP site at: ftp://data.nodc.noaa.gov/pub/data.nodc/pathfinder with subsetting available through the PO.DAAC interface at: http://podaac.jpl.nasa.gov/poet and global files through the ftp://podaac.jpl.nasa.gov. Users are encouraged, where possible, to use Version 5;0. Version 4.1 is being kept on-line to facilitate the transition between different file structures and formats. It is anticipated that phasing ouf of Version 4.1 wiil occur in 2005.

In addition to the increased spatial resolution of 4km versus 9km, enhanced ice and land masks have been applied. Thus where version 4.1 contained gridded files of (4096x2048) pixels, version 5.0 contains (8192x4096) pixels. Several other differences exist in the file structure. In version 5 the parameters, SST, quality flags, and number of observations per bin are contained in separate files. Additionally version 5 comes in the HDF-SDS (scientific data set) format while in version 4.1 the data was in the HDF raster format. Software has been updated on the FTP site to reflect these changes. Data is available from 1985-current through the ESIP POET interface at http://podaac.jpl.nasa.gov/poet or through the ftp site at ftp://podaac.jpl.nasa.gov.

The NOAA/NASA AVHRR Oceans Pathfinder version 4.1 all-pixel data product consists of daily, 8-day and monthly sea surface temperature (SST) derived from the 5-channel Advanced Very High Resolution Radiometers (AVHRR) on board the NOAA-7, 9, 11, 14, 16 and 17 polar orbiting satellites. The data is in the Hierarchical Data Format (HDF) Raster Format for version 4.1. Three parameters are contained in each file, SST, quality flags, and the number of observations per bin. A quality flag of 0 indicates the lowest quality and a quality flag of 7 is the highest. Quality flags are assigned based on a tree algorithm implemented by the University of Miami. The 9km data are on equal-angle grids of 4096 pixels longitude by 2048 pixels in latitude. Data for version 4.1 currently exist from 1985-July of 2003. Additional 18km and 54km grids are also available. For more information on this version and detailed information on the pathfinder algorithm see: ftp://podaac.jpl.nasa.gov/documents/dataset_docs/avhrr_pathfinder_sst.html

Data Set Volume: 4km approximately 14 MB per SST file, 1.2MB per quality flag file, and 6.3 MB per number of observation file.

Data Format: All data are provided in HDF, but in SDS, not raster format.

Media Format: Data are available via anonymous FTP to podaac.jpl.nasa.gov in the pub/sea_surface_temperature/avhrr/pathfinder directory or through the POET interface found at: http://podaac.jpl.nasa.gov/poet.