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PNSWSH
Technical
Implementation Notice 10-55... Amended
National
Weather Service Headquarters
1045 AM EST Tue Jan 18 2011
To:
Subscribers:
-Family of Services
-NOAA Weather Wire Service
-Emergency Managers Weather Information Network
-NOAAPORT
Other NWS Partners, Users and Employees
From:
Timothy McClung
Chief, Science Plans Branch
Office of Science and Technology
Subject:
Amended: Climate Forecast System Changes:
Effective February 22, 2011
Amended to reschedule the implementation
from January 18, 2011, to February 22, 2011, to allow for further evaluation.
Also, it has been decided to continue to run the current version of the CFS,
Version 1, until June 28, 2011, to allow users time to transition their
processes to the new CFS, Version 2.
Effective Tuesday, February 22, 2011,
beginning with the 1200
Coordinated Universal Time (UTC) run, the
National Centers
for Environmental Prediction (NCEP) will
upgrade the Climate
Forecast System (CFS). All components of
the CFS--the
atmospheric model, ocean model,
land-surface model, and data
assimilation--will be upgraded as part of
this change.
Users must upgrade their process of
obtaining CFS data as there will be major changes in content, format, volume of
data, and data dissemination source with this upgrade.
NCEP will continue to run the current
version of the CFS until June 28, 2011, to allow users to transition to the new
CFS output.
A 3-layer interactive global sea ice model,
as well as a global
land data assimilation will be introduced
to the CFS. The resolution of the atmospheric forecast model will be increased
from T62 (
land model. For more details on the upgrades
to the forecast model and products, please check the CFS website at:
http://cfs.ncep.noaa.gov/cfsv2.info
The data assimilation for the Climate
Forecast Model will also be upgraded. The resolution of the Atmospheric Climate
Data Assimilation Version 2 (CDAS2) will be upgraded from T62 (
http://cfs.ncep.noaa.gov/cfsv2.info
There will be significant additions to
parameters in the pressure grib (PGRB), flux files
(FLX) and ocean (OCN) files. In addition, there will be a new file that
contains parameters on isentropic surfaces (IPV).
Due to the increases in resolution, there
will be significant changes to the format, content and sizes of all these
files. The horizontal resolution of PGRB files will increase from 2.5 x 2.5
degree to 1 x 1 degree and the number of pressure levels will increase from 17
to 37. The size of the flux file will increase from the Gaussian grid for T62
(192X94) to that for T126 (384X190). The ocean file will increase from 2.5 x
2.5 degree to
0.5 x 0.5 degree. The new isentropic file will have a resolution of 1 x 1
degree. There will also be an increase in the temporal resolution of the output
forecast data, from 12-hourly to
6-hourly. For more detailed information
about changes/additions to these files, please check the CFS website at:
http://cfs.ncep.noaa.gov/cfsv2.info
Another significant change will be the
discontinuance of all seasonal products, both for the real time forecasts and climatologies. Only monthly mean products will be
disseminated.
A set of test data is available at the CFS
website at:
http://cfs.ncep.noaa.gov/cfsv2.info
The current CFS output is disseminated via
both the NWS FTP server and the NCEP server. With this upgrade, there
will no longer be CFS output disseminated from the NWS FTP server at:
ftp://tgftp.nws.noaa.gov/SL.us008001/ST.opnl/
in the MT.cfs_MR.clim or MT.cfs_MR.fcst directories. All CFS output,
along with the climatologies, will be made available
only on the NCEP server and NOMADS. Beginning on February 22, 2011, CFS
output from the current day will be available via http and ftp at:
http://www.ftp.ncep.noaa.gov/data/nccf/com/cfs/prod
and
ftp://ftp.ncep.noaa.gov/pub/data/nccf/com/cfs/prod
CFS output from the previous 7 days will be
available
http://nomads.ncep.noaa.gov/pub/data/nccf/com/cfs
Data delivery timing of the CFS will be
changed by this implementation. The new CFS will run longer than the
current CFS, and therefore disseminate the products at a later time.
A consistent parallel feed of data has been
available on the NCEP server since late December 2010, at the following URL:
http://www.ftp.ncep.noaa.gov/data/nccf/com/cfs/para/
and
ftp://ftp.ncep.noaa.gov/pub/data/nccf/com/cfs/para/
NCEP encourages all users to ensure their
decoders are flexible and are able of adequately handling changes in content,
changes in the scaling factor component within the product definition section
(PDS) of the GRIB files, and any volume changes which may occur.
If you have any
questions concerning these changes, please contact:
Suranjana Saha
NCEP/Global Climate and Weather Modeling
Branch
301-763-8000 X7236
or
Shrinivas Moorthi
NCEP/Global Climate and Weather Modeling
Branch
301-763-8000 X7233
NWS
National Technical Implementation Notices are online at:
http://www.nws.noaa.gov/os/notif.htm
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