[nws-changes] 20110302: GFS upgrade Fwd: ADMIN NOTICE NOUS41 KWBC

• To: nws-changes@xxxxxxxxxxxxxxxx
• Subject: [nws-changes] 20110302: GFS upgrade Fwd: ADMIN NOTICE NOUS41 KWBC
• From: Linda Miller <lmiller@xxxxxxxxxxxxxxxx>
• Date: Wed, 02 Mar 2011 06:33:18 -0700

-------- Original Message --------

128
NOUS41 KWBC 021255
PNSWSH

Technical Implementation Notice 11-07
National Weather Service Headquarters Washington DC
755 AM EST Wed Mar 2 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
            Science Plans Branch Chief
            Office of Science and Technology

Subject:    Global Forecast System (GFS) Upgrade:
            Effective April 26, 2011

Effective April 26, 2011, beginning with the 1200 Coordinated
Universal Time (UTC) run, the National Centers for Environmental
Prediction (NCEP) will upgrade the Global Forecast System (GFS).
The upgrade includes:

Analysis Changes:
  --Improve Ozone Monitoring Instrument (OMI) quality control
  --Remove redundant SBUV/2 total ozone
  --Retune SBUV/2 ozone observation errors
  --Relax AMSU-A Channel 5 quality control
  --Update Community Radiative Transfer Model(CRTM) to version
    2.0.2
  --Include field of view size/shape/power for radiative
    transfer
  --Remove down weighting of collocated radiances
  --Limit moisture>= 1.e-10 in each outer iteration and at
    end of analysis
  --Include uniform (higher resolution) thinning for satellite
    radiances
  --Improve location of buoys in vertical (move from 20m to
    10m)
  --Improve Gridpoint Statistical Interpolation (GSI) code
    with optimization and additional options
  --Recompute background errors
  --Include SBUV from NOAA-19
  --Ambiguous vector quality control for ASCAT (type 290) data

Model Changes:
  --Set new thermal roughness length
  --Set minimum moisture value in Stratosphere to 1.0x10-7
  --Reduce background diffusion in the Stratosphere

Product Changes:
  -Correct error in the 192 hr, 12-hr precipitation bucket

The three model changes and the 192 hr precipitation change
listed above are designed to address shortfalls introduced with
the 27 July 2010 GFS resolution increase. The issues being
addressed are:

  --Increased low level warm bias over land
  --Negative temperature bias in the stratosphere
  --Negative wind speed bias in the stratosphere
  --Error in the calculation of the 12 hr accumulated
    precipitation at 192 hrs only.

Data Availability:

The format and content of all GFS data sets will remain
unchanged. GFS data is currently available on NOAAPORT, the NWS
FTP server, the NCEP server and in NOMADS. The location of the
data will remain unchanged.

Product delivery timing of the GFS products is not expected to
change as a result of this implementation. More information
regarding the GFS and associated products can be found at:

http://www.emc.ncep.noaa.gov/GFS/doc.php

A consistent parallel feed of data will become available on the
NCEP server once the model is running in parallel on the NCEP
Central Computing System by mid-March.  The parallel data will
be available via the following URLs:

http://www.ftp.ncep.noaa.gov/data/nccf/com/gfs/para

ftp://ftp.ncep.noaa.gov/pub/data/nccf/com/gfs/para

NCEP encourages all users to ensure their decoders are flexible
and are able to adequately handle changes in content order,
changes in the scaling factor component within the product
definition section (PDS) of the GRIB files, and also any volume
changes which may be forthcoming. These elements may change with
future NCEP model implementations. NCEP will make every attempt
to alert users to these changes prior to any implementations.

For questions regarding these changes, please contact:

  John Derber
  NCEP/EMC, Global Climate and Weather Modeling Branch
  Camp Springs, Maryland
  301-763-8000 x 7740
  John.Derber@xxxxxxxx

  John H. Ward
  NCEP/EMC, Global Climate and Weather Modeling Branch
  Camp Springs, Maryland
  301-763-8000 x 7185
  John.Ward@xxxxxxxx

For questions regarding the dataflow aspects of these data
sets, please contact:

  Rebecca Cosgrove
  NCEP/NCO Dataflow Team
  Camp Springs, Maryland 20746
  301-763-8000 x 7198
  ncep.list.pmb-dataflow@xxxxxxxx

NWS National Technical Implementation Notices are online at:

  http://www.weather.gov/os/notif.htm

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