Campaign: Advanced Very High Resolution Radiometer Oceans Pathfinder Sea Surface Temperature Data Sets (AVHRR Pathfinder SST v5)
The 4 km AVHRR Pathfinder Version 5 SST Project (Pathfinder V5)
is a new reanalysis of the AVHRR data stream developed by the University of Miami's Rosenstiel School of Marine and Atmospheric Science (RSMAS)
and the NOAA National Oceanographic Data Center (NODC). In partnership with NODC and RSMAS is NASA's Physical Oceanography Distributed Active Archive
Center (PO.DAAC), which has years of experience serving and developing earlier versions of the Pathfinder dataset. Currently in the third year of a
three-year demonstration effort, it is hoped that this system can be implemented as an ongoing effort as part of a broader SST climate data record
system.
Provenance: local copy of the 4 km AVHRR Pathfinder Version 5 SST Monthly Means Data Set (daytime measurements) downloaded via FTP from: ftp://podaac.jpl.nasa.gov/pub/sea_surface_temperature/avhrr/pathfinder/data_v5/monthly/day/04km/. Files are located under WELLE.ZMAW.DE:/scratch/local3/u290022/DATA/SATELLITE/AVHRR/pathfinder/data_v5/monthly/day/04km/.
The 4 km AVHRR Pathfinder Version 5 SST Project (Pathfinder V5) is a new reanalysis of the AVHRR data stream developed by the University of Miami's Rosenstiel School of Marine and Atmospheric Science (RSMAS) and the NOAA National Oceanographic Data Center (NODC). In partnership with NODC and RSMAS is NASA's Physical Oceanography Distributed Active Archive Center (PO.DAAC).
Methods: this reprocessing uses an improved version of the Pathfinder algorithm and processing steps to produce twice-daily global SST and related parameters back to 1981, at a resolution of approximately 4 km, the highest possible for a global AVHRR data set. Temporal averages for 5-day, 7-day, 8-day, Monthly, and Yearly periods are also produced. Current key improvements over the original 9 km Pathfinder SST data set include a more accurate, consistent land mask, higher spatial resolution, and inclusion of sea ice information. Additional improvements including better flagging of aerosol-contaminated retrievals and the provision of wind and aerosol ancillary data will be implemented in a future Version 6 reprocessing. Additionally the parameters in version 5.0 are contained in separate files which are in the HDF-SDS (scientific data set) format, unlike version 4.1 which was in HDF-RASTER. The data can be accessed via the NODC, see http://www.nodc.noaa.gov/SatelliteData/pathfinder4km for more information regarding user guide, tools, available data, quality, etc.
The data can also be accessed via NASA's PO.DAAC website, see: http://podaac.jpl.nasa.gov/PRODUCTS/p216.html
The overall quality flag is a relative assignment of SST quality based on a hierarchical suite of tests. It varies from 0 to 7, (0 being the lowest qu...
Description
The overall quality flag is a relative assignment of SST quality based on a hierarchical suite of tests. It varies from 0 to 7, (0 being the lowest quality and 7 the highest). For most applications, using SST observations
with quality levels of 4 to 7 is typical. For applications requiring only the best-available observations
(at the expense of the number of observations), use quality levels of 7 only.
For more information regarding the suite of tests, see Kilpatrick et al. (2001). Further information: http://www.nodc.noaa.gov/sog/pathfinder4km/userguide.html.
Several quality assurance steps are conducted to insure the integrity of the data provided here. These steps are conducted routinely during
the processing and transfer stages of the system. Note that these steps are aimed primarily at assuring items like file integrity and availability, not at the accuracy of the derived sea surface temperature (SST) values. That type of quality control is integral to the Pathfinder processing through derivation of parameters like the overall quality flag and quality mask values, as well as post-processing studies being carried out to test the satellite SSTs against in situ observations.
The steps to insure file integrity are outlined in: http://www.nodc.noaa.gov/SatelliteData/pathfinder4km/qa.html
[1] DOIBrown, James W.; Brown, Otis B.; Evans, Robert H. (1993). Calibration of advanced very high resolution radiometer infrared channels: A new approach to nonlinear correction. doi:10.1029/93JC01638
[2] DOIKilpatrick, K. A.; Podestá, G. P.; Evans, R. (2001). Overview of the NOAA/NASA advanced very high resolution radiometer Pathfinder algorithm for sea surface temperature and associated matchup database. doi:10.1029/1999JC000065