= High Impact     = Moderate Impact     = Low Impact

(Dates show approximate starting production date)

Aerosol (04_L2) and Water Vapor (05_L2) HDF products are produced from the Program Executable (PGE) identified as PGE04. One may identify the maturity and quality of an HDF data product by finding the PGE (program executable) version that was used to produce the file. This information can be obtained directly from the HDF file itself by using the HDF utility ncdump. The (UNIX) command is ncdump -h *.hdf | awk '/PGEVERSIONCLASS/,/END_GROUP/' . One may also find PGE version information in the ascii text met (metadata) file associated with a particular HDF file. Another slightly less reliable way to determine the PGE version is through the "processing date & time" field of the HDF filename (field #5 in L2 HDF files, see HDF Filename convention). Users then match the processing date in the HDF filename with the production start date for various PGE versions in blue in the listing below. If you have any questions about this, contact Paul Hubanks.

PGE04 v5.3.7 includes:       ( Aqua (only) Forward & Reprocess: ~1.Jan.2007 )

• Implementation of Deep Blue Aerosol
  Added Deep Blue Aerosol. The current MODIS aerosol retrieval algorithm is based on the Dark Target approach and as a result it provides less reliable or no retrieval data over desert and other highly reflecting land surfaces. To improve the quality of desert and bright surface retrievals, the aerosol team has implemented this initial version of the Deep Blue retrieval algorithm which compliments the existing Dark Target method.
  

PGE04 v5.2.5 includes:       ( Terra Forward & Reprocess: ~1.Feb.2006 )

• Initial Collection 005 Version
  Start of C005. See Aerosol and Water Vapor change documents (PDF) linked from the Collection 005 Update page to view Collection 004 to Collection 005 changes and improvements.