General PGE Information
The MOD06_L2 and MYD06_L2 products are produced from the Program Executable (PGE) identified as PGE06.
To determine the current PGE06 version that has completed:
1) baseline procedure,
2) integration & testing, and
3) MODAPS operations implementation, visit the
PGE Status Chart.
For information on reconciling Algorithm process version and PGE version, visit the
PGE06 Version History File.
Tool/Command for PGE Determination
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 for finding the PGE version that was used to create a particular HDF file is
ncdump -h *.hdf | awk '/PGEVERSIONCLASS/,/END_GROUP/'
One may also find PGE version information in the ascii met (metadata) file associated with a particular HDF file.
PGE06 Algorithm History - Product Impact Changes
- Cloud Optical Products (06_L2)
Product Generation Executive (PGE): PGE06 v6.0.72
Archive Production Time Period: 7/2002-12/2012
The intended maximum reported value for a successful Cloud Optical Thickness (COT) retrieval was increased from 100 in Collection 5 to 150 in Collection 6 (C6). However the new C6 COT datasets Cloud_Optical_Thickness_16 and Cloud_Optical_Thickness_37 were inadvertently not limited to 150. Therefore, for a small number of very bright clouds (typically at low sun angles), these two COT datasets can exceed 150 or become negative due to an integer overflow (beyond a value of 327.67). Users are advised that if they encounter a COT value in these datasets that is either greater than 150, or less than zero but not a fill value, then they should set the value to 150.
Product Generation Executive (PGE): PGE06 v6.0.75
Archive Production Time Period: 1/2013-present
This minor COT dataset issue has been remedied for Aqua forward processing starting on a production date of April 21, 2014 (2014111). Since the problem was found before Terra reprocessing began, no Terra re-/forward-processing was impacted.