The NASA A-Train satellite constellation has acquired twelve years of
remotely sensed observations, containing detailed information about
atmospheric processes. This talk describes some of the challenges of
extracting and interpreting that information. Examples will be shown from
the Atmospheric Infrared Sounder / Advanced Microwave Sounding Unit suite
(AIRS/AMSU), which has acquired about one billion atmospheric soundings
since launch in 2002. Some of the challenges of interpreting the
AIRS/AMSU observations in the context of a wide variety of A-Train data
will also be described.