***************************************************************** Journal for accession number: 0156457 Created on: 2016-08-31 11:32:11 UTC By: Automated Ingest Agent Source: This accession contains AVHRR Pathfinder Version 5.3 Level 3 Collated 4 km Sea Surface Temperature from 1983-01-01 to 1983-12-31 (NCEI Accession Number 0156457) The AVHRR Pathfinder Version 5.3 (PFV53) Level 3 Collated (L3C) Sea Surface Temperature data set is a collection of global, twice-daily (Day and Night) 4km sea surface temperature (SST) data produced by the NOAA National Centers for Environmental Information (NCEI). L3C data contains daily SST along with other ancillary data: wind_speed, sea_ice_fraction, aerosol_dynamic_indicator, dt_analysis (difference between satellite SST measurements and a defined reference climatology of SST), quality_level (GHRSST quality levels), pathfinder_quality_level, and l2p_flags. Actions: NCEI acquires Level 1b AVHRR Global Area Coverage (GAC) data and processes it to globally gridded Level 3 data files in HDF4 using code based on the SeaDAS v6.4 processing environment. NCEI then converts these files to netCDF4 files compliant with the Group for High Resolution Sea Surface Temperature (GHRSST) Data Specification Version 2.0 (GDS2.0 revision 5). Final PFV53 data are quality assured through browse image generation and visual inspection. Upon completion of the quality assurance routines, the data along with the images are archived in multiple accessions, each holding a year of data, beginning with 1981. The data are then archived and published online by NCEI. In comparison to version 5.2 (PFV52), the PFV53 are updated with following changes: 1. SSTs are now available for all quality levels, including quality of 0 which was left out of PFV52 due to a memory issue in the version 5.2 code. 2. Sun glint regions are better included in the data. 3. Cloud tree tests for NOAA-7 and NOAA-19 are consistent now with the rest of the sensors in contrast to PFV52 where they were inconsistent. 4. PFV53 also includes L2P (Level 2 Pre-processed) and L3U (Level 3 Uncollated) product levels for the very first time. All previous versions of Pathfinder only included L3C products. These L2P and L3U are archived in a separate set of accessions. 5. PFV53 L2P and L3U include the sst_dtime variable; However, it is still not included in L3C (it was not included in PFV52 either). 6. The global and variables attributes in netCDF files are revised, have better CF and ACDD compliance, and are consistent with the NCEI netCDF templates. 7. Anomalous hot-spots at land-water boundaries are better identified and flagged in PFV53. 8. The PFV53 land mask has been updated (based on Global Lakes and Wetlands Database: Lakes and Wetlands Grid Level 3, 2015). 9. Sea ice data over the Antarctic ice shelves are marked as ice and flagged as 100% ice cover. 10. The PFV53 output are netCDF version 4 in classic mode. In PFV52 the netCDF-4 files were not explicitly identified as "classic". 11. An update in code that fixes the binary search used to find the appropriate one line orbital elements for the granule being processed. 12. An extra bit (bit 6) is used under l2p_flags variable to flag out the daytime unrealistic SST values (>39.8°C) that remain in pf_quality_level 4 to 7. Users are recommended to avoid these values. Once the data were produced by NCEI, this archival information package (NCEI Accession) was generated. The files in netCDF format were copied to the data/0-data/ directory along with their corresponding browse images in .png format. Files: Files in this accession include PFV53 L3C browse images and data files for the whole period. about/ This directory contains files created by NCEI staff, including 'negotiable' information between NCEI staff and the data provider. journal.txt - This file. 0156457_preview.png - Sample of a global map for Level-3C Sea Surface Temperature data from PFV53. data/0-data/ This directory contains PFV53 data and graphic files in NetCDF and PNG format respectively, for the whole accession period.   The file naming convention for the GHRSST GDS 2.0 is described in GDS2.0 revision 5 Technical Specifications: GDS_TechSpecs_v2.0.pdf (GHRSST documentation, NODC Accession 0123222) netCDF file: --_GHRSST----v-fv. graphic file: --_GHRSST----v-fv_. Many code lists and details are associated with this convention. Note carefully that dashes ("-") separate parts of the file name, while underscores ("_") are used within the parts of the file name. For Pathfinder Version 5.3 data: * Indicative date and time are, by GDS2 definition, for the central time of the collation window and use YYYYMMDD and HHMMSS format * Processing level = "L3C" for Level 3 Collated * SST Type = "SSTskin" * Character String = "AVHRR_Pathfinder" * Additional Segregator = PFV5.3_NOAAXX_G_YYYYDDD_DAYNIGHTCODE where: * XX = two-digit NOAA POES satellite identifier from 07, 09, 11, 14, 16,17, 18, 19 * YYYYDDD = four digit year and three-digit day of year. Note that for some Pathfinder Version 5.3 files, this YYYYDDD can be shifted by a day compared to the "Indicative Date and Time, which is defined in the GDS2.0 for L3C files as the central time of the collation window. Sometimes this falls just over midnight, and can result in a given day having apparently two files and the next day none. This YYYYDDD is comparable to the date used in Pathfinder Version 5.0, 5.1 and 5.2. * DAYNIGHTCODE = "day" or "night", indicator of whether this collated file represents daytime data or nighttime data. * "_G" refers to Global Area Coverage (GAC) data. * GDS Version = Version number of the GDS used to process the file. For example, GDS 2.0 = "02.0"; * File Version = Version number for the file, for example, "01.0";. * browse_image_variable = these variables listed under the data/0-data/ directory: "sea_surface_temperature"; "dt_analysis"; "wind_speed"; "sea_ice_fraction"; "aerosol_dynamic_indicator"; "quality_level"; "pathfinder_quality_level"; "l2p_flags"; "declouded_sst". Thus, the convention for Pathfinder Version 5.3 is: YYYYMMDDHHMMSS-NCEI-L3C_GHRSST-SSTskin-AVHRR_Pathfinder-PFV5.3_NOAAXX_G_YYYYDDD_DAYNIGHTCODE-v02.0-fv01.0.nc YYYYMMDDHHMMSS-NCEI-L3C_GHRSST-SSTskin-AVHRR_Pathfinder-PFV5.3_NOAAXX_G_YYYYDDD_DAYNIGHTCODE-v02.0-fv01.0_browse_image_variable.png noting that the YYYYMMDD and YYYYDDD might not exactly match, but could be different by one day. Example files: * netCDF file: 19810825011936-NCEI-L3C_GHRSST-SSTskin-AVHRR_Pathfinder-PFV5.3_NOAA07_G_1981237_night-v02.0-fv01.0.nc * graphic file: 19810825011936-NCEI-L3C_GHRSST-SSTskin-AVHRR_Pathfinder-PFV5.3_NOAA07_G_1981237_night-v02.0-fv01.0_sea_surface_temperature.png