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NOUS41 KWBC 181341
PNSWSH
Technical Implementation Notice 10-55... Amended
National Weather Service Headquarters Washington DC
1040 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 (210 km) to T126 (100 km). The ocean forecast model
will be upgraded from the limited area GFDL MOM3 to the global
MOM4. The horizontal resolution will increase from 0.33 degree
to 0.25 degree from 10 North to 10 South latitudes. Northwards
and southwards to the poles, the resolution will increase from
1 degree to 0.5 degree globally. The land surface model will be
upgraded from the 2-level OSU Model to the 4-level NOAH
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 (210
km) with 28 sigma levels to T574 (27km) with 64 hybrid sigma-
pressure levels. The Spectral Statistical Interpolation Scheme
(SSI) will change to a Gridpoint Statistical Interpolation
Scheme (GSI). Satellite radiances will be directly assimilated
instead of retrievals. The Global Ocean Data Assimilation
(GODAS) will also be upgraded from MOM3 to MOM4. In addition,
there will be a new Global Land Data Assimilation (GLDAS) which
will use observed Climate Prediction Center (CPC) precipitation
as forcing for the NOAH land model. For more details on the
upgrades to the data assimilation and products, please check the
CFS website at the link below.
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
on NOMADS at:
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
Camp Springs, Maryland
301-763-8000 X7236
suranjana.saha@xxxxxxxx
or
Shrinivas Moorthi
NCEP/Global Climate and Weather Modeling Branch
Camp Springs, Maryland
301-763-8000 X7233
shrinivas.moorthi@xxxxxxxx
NWS National Technical Implementation Notices are online at:
http://www.nws.noaa.gov/os/notif.htm
$$
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