SUPPLEMENTARY DOCUMENTATION
Background information about this type of data may be
found in An Introduction to Atmospheric and Oceanographic Datasets.
INFORMATION ABOUT THE NCEP GDAS FNL 1.0 DEGREE 6-HOURLY ANALYSIS UPDATES
The CISL/DSS archived FNL analysis filenames have the form fnl_yymmdd_hh_00[_c] ,
the yymmdd_hh is in Coordinated Universal Time (UTC, UT, GMT or Z). The
_00 in this form indicates that the file is an analysis, not a forecast.
Files published on the CISL/DSS web site are grib1. Beginning 2008.09.30.12, when
a filename is appended with "_c", it means CISL/DSS converted it from grib2 to grib1.
The CISL/DSS FNL files originated as downloads of the near-real time analysis files on the
NCEP file server, from the
pub/data/nccf/com/gfs/prod/gdas.[date] directories, where date has the form
yyyymmdd , and the files are named gdas1.thhz.pgrbf00.grib2 where hh is the analysis
time and f00 indicates an analysis. pgrb files with other fnn values are forecasts
nn hours into the future. Numerous other files are in these directories. The NCEP
directories are emptied after about 30 hours, and aged off after about 48 hours.
CISL/DSS selects the FNL analysis over all others because it uses the most complete set of observations and is 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.
Please see the NCEP
document About the Global Parallel System.
and the EMC Model Documentation
for more details.
As with any high volume operational model production system there are times when late file postings and
network outages interrupt data acquisition and processing for the archive. The CISL/DSS makes a "best"
effort to sustain a complete archive time series. Recoveries from short-term problems are handled
systematically. For longer-term problems we obtain assistance from NCEP staff.
VARIABLES:
Land skin temperature and sea surface temperature are in one field.
LEVELS:
1000mb 975mb 925mb 900mb 850mb 800mb 700mb 650mb 600mb 550mb 500mb 450mb 400mb
350mb 300mb 250mb 200mb 150mb 100mb 70mb 50mb 30mb 20mb 10mb
surface upper-air troposphere mandatory tropopause stratosphere
FORMAT AND USAGE:
General
To see the WMO's GRIB Documentation click here.
To see NCEP's GRIB1 Documentation click here.
To see NCEP's GRIB2 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 NCAR/MMM's MM5 click here.
For support using ATMET's RAMS click here.
 |
| Updated 22 July 2005 |
