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Data format for GSI

The GSI can analyze many types of observational data, including conventional data, satellite radiance obervations (such as AIRS, IASI, SBUV/2 ozone, GOME ozone, GOES sounder, GOES imager, AVHRR), GPS radio occultation observations (bending angle or refractivity) and radar data. For use with the GSI, conventional observations are saved in the PrepBUFR format (BUFR format with NCEP specified features) and other data are saved in the starndard BUFR format. A detailed introduction to PrepBUFR/BUFR can be found in the GSI Users' Guide (Version 3-Chapter 8: PrepBUFR/BUFR).

Observation data in forms other than PrepBUFR/BUFR must be converted to PrepBUFR/BUFR before they can be used in the GSI. Here is a list of useful websites on this issue:

NCEP/NCO websitr to introduce BUFRLIB and how to decode and encode BUFR files: link

BUFR documents also can be found in NCAR DSS: link

PREPBUFR documents at NCEP: link

Observation data processing at NCEP (by Dennis Keyser): link

Data Hubs for PrepBUFR/BUFR Data

The follow is a list of data center that has meteorological histroy data in PREPBUFR format :

• NCEP NOMADS Site:
  • PrepBufr for GDAS (Global) - 1 month buffer:
    http://nomads.ncep.noaa.gov/pub/data/n ccf/com/gfs/prod
  • PrepBufr for NDAS (North America) - 1 month buffer:
    http://nomads.ncep.noaa.gov/pub/data/n ccf/com/nam/prod
• NCDC NOMADS Site:
  • PrepBufr for GDAS (Global) - archive starting May 2007:
    http://nomads.ncdc.noaa.gov/data/gdas
    *** NOTE: The 18Z filenames are incorrect on this site. The date listed in the filename is one day later than the observations actually contained in the file. ***
• NCAR CISL Site:
  • DS337.0: NCEP ADP Global Upper Air and Surface Observations (PREPBUFR and NetCDF PB2NC Output) - arch ive starting May 1997:
    http://dss.ucar.edu/datasets/ds337.0
  • DS337.0 Subset: Interactive tool for running PB2NC over a specified time period and geographic region :
    http://dss.ucar.edu/datasets/ds337. 0/forms/337_subset.php