[Esip-infoquality] A different perspective on quality from GODAE

Lynnes, Christopher S. (GSFC-6102) christopher.s.lynnes at nasa.gov
Tue Jun 7 08:18:54 EDT 2011

Interesting...GODAE kind of equates quality level with processing level:  http://www.godae.org/Data-definition.html.  

I guess there may be some truth to that, in that you discard more and more suspect values as you go up the processing level chain:
L0 = raw data, keep everything
L1B = probably keep everything, but flag suspect quality based on calibration
L2 = discard individual pixels where retrievals are impossible or (sometimes) where they are highly suspect
L3 = (usually) do not include suspect pixels in grid averages
L4 = use only the best retrievals for assimilation

Of course, most levels carry exceptions:
L0 = delete packets with incorrect timestamps or apparent bit-level corruption 
L2 = keep only values that pass strict quality control (e.g., AIRS CO2)
L3 = keep all retrievals (MODIS Image_Optical_Depth)
Christopher Lynnes     
Goddard Earth Sciences Data and Information Center, NASA/GSFC

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