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SUPPLEMENTARY DOCUMENTATION

Background information about this type of data may be found in An Introduction to Atmospheric and Oceanographic Datasets.

As with any high volume operational model production system there were times when late file postings and network outages interrupted data acquisition and processing for the archive. The CISL/DSS made a "best" effort to obtain a complete archive time series.

CISL/DSS selected the FNL analysis over all others because it used the most complete set of observations and was run last in the sequence of operational global models. The FNL is likely the best option for a long-term operational model archive from NCEP. Note that NCEP also made the Aviation (AVN) Analyses using the same model, but DSS did not collect them.

Correspondence received from NCEP in June 1992 indicates that the production of the global analyses was given second priority. They considered it their most expendable product. When they experienced hardware failures and the like, they gave the MRF model priority, and sometimes (especially at 00Z) this meant skipping the final run which produced the global analyses.



INFORMATION ABOUT THE NCEP GDAS FNL 2.5 DEGREE 12-HOURLY ANALYSIS METHODOLOGY

Please see the NCEP documents About the Global Parallel System. and EMC Model Documentation for more details.




VARIABLES:

Land skin temperature and sea surface temperature are in one field.

A memo about SST analysis is here.

As in DS082.0, the temperature may still actually be a virtual temperature.

NCEP dropped Tmax and Tmin in late 1999




LEVELS:

1000mb 850mb 700mb 500mb 400mb 300mb 250mb 200mb 150mb 100mb 70mb 50mb 30mb 20mb 10mb

surface upper-air troposphere mandatory tropopause stratosphere sigma

A surface subset has been built by DSS in DS083.1.

For higher levels (70 to 0.4mb), which are on polar grids, please see DS067.3.




FORMAT AND USAGE:

General

To see the WMO's GRIB Documentation click here.
To see NCEP's GRIB1 Documentation click here.
To see FAQs about FNL and ADP data click here.

Tools to manipulate GRIB data

For support using NCAR/CISL's NCL click here.
For support using COLA's GrADS click here.

Models

For support using NCAR/MMM's WRF click here.
For support using ATMET's RAMS click here.



The Research Data Archive is managed by the Data Support Section of the Computational and Information Systems Laboratory at the National Center for Atmospheric Research in Boulder, Colorado. NCAR is sponsored by the National Science Foundation.

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