This documentation was written by Paul Poli in April 2006 and is regularly updated since then.

The OBSTAT software computes and plots statistics on observations assimilated in the
ECMWF or Meteo France assimilation suite. One common application of OBSTAT is to
produce statistics of observation minus background and observation minus analysis quantities.
One assimilation time period is sufficient to run OBSTAT, but statistics over several
assimilation time periods can be cumulated to produce statistics over an entire experiment, for
example.
OBSTAT relies on the Observation Data Base (ODB) to extract the observation minus first

• 13/03/2006 P. Poli 0.0 First version.
• 15/03/2006 P. Poli 0.1 Enhanced section IV to enable use of text outputs from OBSTAT.
• 01/03/2007 P. Poli 0.2 Addition of observation and background error diagnostics
• 27/07/2007 P. Poli 0.21 Q&A: How to deal with inisoftstat problems, How to define new
  domains, How to compare two experiments using different cycles.
• 19/02/2008 P. Poli 0.3 Upgrade for cycle 33; support for IASI, SEVIRI and ASCAT
• 10/04/2008 P. Poli 0.4 Support for 3-hour cutoffs
• 17/04/2008 P. Poli 0.5 Support for radar winds
• 04/06/2008 P. Poli 0.6 Major change after phasing with ECMWF CY33R2. Change of item numbers.

see joined pdf file