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DDDDay of year
GGGGNSS id (G28 = GPS satellite 28)
IIIIMission ID (CHAM, SACC, CO01-06, GPSM, etc)
LLLLEO number (1-6 for COSMIC)
MISSIONMission ID (eight characters or less--champ, champrt, sacc, sacctst, etc)
PUBBase directory for the pub hierarchy
SSSSSubtype (an ID which tells the command options used in generating this file)
VVVVVersion (an ID which tells the version of all codes using in generating thie file)

A low resolution (adjustable, currently 200 meter) atmospheric profile in the BUFR format useful to weather modelers. Contains data taken from the atmPhs, atmPrf and wetPrf files, including:

  • Occultation location and time, other header information
  • Bending angle versus impact parameter profiles
  • Refractivity versus MSL geometric height profiles
  • Pressure, Temperature and Moisture versus geopotential height profiles

The complete format documentation is in the Version 2.3 WMO FM94 (BUFR) Specification (PDF) by Dave Offiler of the UK Met Office.

Some notes are in order as to the UCAR/COSMIC implementation of the above BUFR format.

The original data from the atmPrf files are specified on a high rate 50 Hz grid (3000 values for a 60 second occultation). Certain data (lat, lon, azim, bending angle, impact parameter, refractivity) are first interpolated onto a uniform high resolution grid, then Fourier smoothed and finally interpolated onto the 200m grid.

Higher level data (pressure, temperature, specific humidity) is supplied in 100 meter resolution in the wetPrf files and is simply decimated to get 200m resolution data.

The current 'percent confidence' vector for both bending angle and refractivity is somewhat rudimentary. It is a simple exponential curve generated from the bending angle noise between 60 and 80 km, modified by several other scalar data quality indicators.

The error values for bending angle and refractivity are only given for high altitude data (above approximately 20km). We hope to supply complete error profiles soon.

There are currently no error values supplied for pressure, temperature and specific humidity.