NOUS41 KWBC 171445
AAA
PNSWSH
Technical
Implementation Notice 14-46 Amended
National Weather
Service Headquarters Washington DC
945 AM EST Mon
Nov 17 2014
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: Global Forecast Systems (GFS)
Update:
Effective January 7, 2015
Amended to change
effective date to January 7, 2015
Effective on or
about January 7, 2015, beginning with the
1200 Coordinated
Universal Time (UTC) run, the National
Centers for
Environmental Prediction (NCEP) will upgrade the
GFS Analysis and
Forecast System which includes:
- Changes to the model components
- Increases in horizontal resolution
- Addition of 0.25 degree gridded output
- New product fields
- Change of product naming convention
- Changes in product timeliness
- Downstream model impacts
1) Model changes
to the GFS Global Spectral Model:
- Increase
horizontal resolution of the first segment of the
forecast from Eulerian T574
(~27 km) to Semi-Lagrangian
T1534 (~13 km),
and extend the length of forecast from 192
hours to 240 hours
- Increase
horizontal resolution of the second segment of
the forecast from Eulerian
T192 (~84 km) to semi-Lagrangian
T574 (~35 km),
and set forecast time from 240 hours to 384
hours
- Change from Eulerian dynamics to Semi-Lagrangian
dynamics,
which uses Hermite
interpolation in both vertical and
horizontal directions.
- Use 5 minute
daily Real-Time Global (RTG) Sea Surface
Temperature (SST)
to replace 1.0 degree Reynolds 7 day SST
analysis
- Initialize ice
at small inland lakes in the northern
hemisphere with 4 km Interactive Multi-sensor Snow and
Ice
Mapping System
(IMS) ice analysis data from the National Ice
Center. For
large water bodies, use 5 minute NCEP/MMAB ice
analysis data to replace 30 minute ice data
- Use 1982-2012 5
minute SST climatology (replacing 1982-
2001
1 degree SST climatology).
- Use 1982-2012
30 minute sea ice concentration climatology
(replacing 1982-2001 1 degree climatology).
- Replace update
of model snow depth by direct insertion of
AFWA depth data
with a blend of the model first guess depth
and the AFWA depth.
- Use X-number to
prepare spectral transform base functions.
X-number is a
numerical technique. It uses paired numbers to
represent real number to avoid computational underflow
or
overflow that can occur in spectral truncation for
wave
number larger than T1000.
- Use divergence
damping in the stratosphere to reduce noise
- Add a tracer
fixer for maintaining global column ozone
mass
- Use the
Monte-Carlo Independent Column Approximation
(McICA) for Rapid Radiative Transfer Model (RRTM) Radiation
- Reduce drag
coefficient at high wind speeds
- Use Hybrid
Eddy-Diffusivity Mass-Flux Planetary Boundary
Layer (EDMF PBL)
scheme and Turbulent Kinetic Energy (TKE)
dissipative heating
- Re-tune ice and
water cloud conversion rates, orographic
gravity-wave forcing and mountain block; and reduce
background diffusion of momentum
- Add stationary
convective gravity wave drag
- Modify
initialization of forecast state variables to
reduce a sharp decrease in cloud water in the first
model
time step
- Correct a bug
in the condensation calculation after the
digital filter is applied
- Replace 1.0
degree bucket soil moisture climatology with
CFS/Global Land
Data Assimilation System (GLDAS) climatology
at T574 (~27 km)
- Replace 1.0
degree momentum roughness length climatology
by using a look-up table based on vegetation
type
- Add a
dependence of the ratio of the thermal and momentum
roughness on vegetation type
2) Model changes
to the GDAS/GFS Hybrid 3D-VAR Ensemble
Kalman Filter (EnKF) Data
Assimilation:
- Increase EnKF resolution from T254L64 to T574L64
- Assimilate
hourly GOES and EUMETSAT atmospheric motion
vectors
- Update radiance
assimilation:
- Assimilate SSM/IS UPP LAS and Metop-B IASI radiances
- Use enhanced radiance bias correction scheme
- Update to version 2.1.3 of the Community
Radiative
Transfer Model (CRTM). CRTM v2.1.3 improves
specification of
microwave sea surface emissivities.
This, in turn, improves the analysis of
near surface
temperature over water,
especially in the southern
oceans.
- Use stochastic physics in EnKF ensemble forecasts
- The dump window for GOES Satellite Wind (satwnd) data
will change from
1 hour to 6 hours. Subtypes will be
added for
(NOAA/METOP AVHRR SATWIND) infrared cloud
motion vector and
(NESDIS/GOES 3.9 micron channel)
derived cloud
motion vector
3) Output product
changes
All filenames
given below can be located on the NCEP ftp
server, the NCEP http server, NOMADS or the NWS ftp
server
respectively via the following URLs (YYYYMMDD is the
year,
month, and day; CC is the cycle):
ftp://ftp.ncep.noaa.gov/pub/data/nccf/com/gfs/prod/gfs.YYYYMMDDCC/
ftp://ftp.ncep.noaa.gov/pub/data/nccf/com/gfs/prod/gdas.YYYYMMDD
http://www.ftp.ncep.noaa.gov/data/nccf/com/gfs/prod/gfs.YYYYMMDDCC/
http://www.ftp.ncep.noaa.gov/data/nccf/com/gfs/prod/gdas.YYYYMMDD/
ftp://tgftp.nws.noaa.gov/nfs/nwstg/ftp/SL.us008001/ST.opnl/MT.gfs_CY.CC/RD.YYYYMMDD/
Product Removals:
With this upgrade
NCEP is removing output files that are
obsolete and not widely used. Please reference this
html for
explanations and possible replacement products:
http://www.nco.ncep.noaa.gov/pmb/changes/gfs_upgrade.shtml
- The following
files will be removed
gfs.YYYYMMDDCC/gfs.tCCz.sstgrb
gfs.YYYYMMDDCC/gfs.tCCz.engicegrb
gfs.YYYYMMDDCC/gfs.tCCz.snogrb
gdas.YYYYMMDD/gdas1.tCCz.engicegrb.grib2
gdas.YYYYMMDD/gdas1.tCCz.sstgrb.grib2
PT.grid_DF.gr2/fh.00xx_tl.press_gr.sstgrb
gdas.YYYYMMDD/gdas1.tCCz.snogrb.grib2
gfs.YYYYMMDDCC/gfs_grb211.tCCz.pgrbFH.grib2
gfs.YYYYMMDDCC/gfs.tCCz.master.grbfFF.10m.uv.grib2
PT.grid_DF.gr2/fh.xxxx_pa.sw10m_tl.press_gr.0p5deg
gdas.YYYYMMDD/gdas1.tCCz.satang
gfs.YYYYMMDDCC/gfs.tCCz.trmm.tm00.bufr_d
gfs.YYYYMMDDCC/gfs.tCCz.sptrmm.tm00.bufr_d
gdas.YYYYMMDD/gdas1.tCCz.sptrmm.tm00.bufr_d
gdas.YYYYMMDD/gdas1.forecmwf.YYYYMMDDCC.grib2
- Remove variables
from GFS and GDAS pressure GRIB files
(*pgrb*)
- Geopotential
Height Anomaly (GPA)
- 5-Wave Geopotential
Height Anomaly (5WAVA)
Current Product
Changes:
- The naming
convention will change to include the grid and
3 digit forecast
hours:
On the NCEP server -
GFS FH = "anl"
or "f000-f384"
GDAS FH = "anl"
or "f000-f009"
gfs.tCCz.pgrb2.fFFF ->
gfs.tCCz.pgrb2.0p50.FH
gfs.tCCz.pgrb2b.fFFF ->
gfs.tCCz.pgrb2b.0p50.FH
gfs.tCCz.pgrb.fFFF.grib2 -> gfs.tCCz.pgrb2.1p00.FH
gfs.tCCz.pgrb2b.fFFF ->
gfs.tCCz.pgrb2b.1p00.FH
gfs.tCCz.pgrb.2p5deg.fFFF.grib2 ->
gfs.tCCz.pgrb2.2p50.FH
gfs.tCCz.pgrb.fFFF.grib2 ->
gfs.tCCz.pgrb2.2p50.FH
gfs.tCCz.goessimpgrb2fFFF.1p0deg ->
gfs.tCCz.goessimpgrb2FH.1p0deg
gfs.tCCz.goessimpgrb2fFFF.grd221 ->
gfs.tCCz.goessimpgrb2FH.grd221
master/gfs.tCCz.mastergrb2fFFF ->
gfs.tCCz.pgrb2full.0p50.FH
gdas1.tCCz.pgrbfFF.grib2 ->
gdas1.tCCz.pgrb2.1p00.FH
On the NWS server:
GFS FH = 000-384
fh.0FH_tl.press_gr.0p5deg ->
fh.0FH_tl.press_gr.0p50deg
fh.0FH_tl.press_gr.1p0deg ->
fh.0FH_tl.press_gr.1p00deg
fh.0FH_tl.press_gr.2p5deg ->
fh.0FH_tl.press_gr.2p50deg
- The following
files will have decreased forecast hour
availability to now only:
gfs.YYYYMMDDCC/gfs.tCCz.bfFF hourly output from 00-12
gfs.YYYYMMDDCC/gfs.tCCz.sfFF hourly output from 00-12
- There are
numerous changes to the operational NOMADS
files. For all of the details please reference
this page:
http://www.nco.ncep.noaa.gov/pmb/changes/gfs_upgrade.shtml
- The packing for
GRIB2 will be switched to secondorder
complex packing. The benefits for users will be much
faster
IO time compared
with the existing JPEG packing. The second
order packing provides good accuracy, although
files will be
slightly larger than JPEG packing.
- Modify the list
of stations for which BUFR data is
generated for the GFS.
The changes will also modify the
lists of stations in the GFS BUFR sounding
collectives
disseminated on NOAAPORT. For the full list please
reference
this page:
http://www.nco.ncep.noaa.gov/pmb/changes/gfs_upgrade.shtml
- Use of the
enhanced radiance bias correction scheme will
be changing the abias
file. The format of the file is being
changed to incorporate information from the satang
file.
gdas.YYYYMMDD/gdas1.tCCz.abias
- The GFS cyclone
tracker file code has changed from "NA" to
"AA"
for storms in the Arabian Sea.
PT.text_GP.tratcf/cyclone.trackatcf
- Change
variables averaged or accumulated over time, such
as precipitation accumulation, to 6 hourly up
to forecast
hour 240 for all products (some had been 12
hourly after
forecast hour 180 and some had been 12 hourly after
forecast
hour 192).
- Modify fields
to both GFS and GDAS:
- Add Frozen Precipitation Fraction (CPOFP)
- Add Ozone (O3MR) at 150, 200, 250, 300,
350, and 400 mb
- Add Dew Point (DPT) at 2 meters
- Add Apparent Temperature (APTMP)
- Add instantaneous precipitation type
(CICEP, CFRZR,
CRAIN, CSNOW)
- Add Membrane SLP in GDAS pressure grib files
- Rename TMP at 0-0.1 m, 0.1-0.4 m, 0.4-1.0
m, and 1-2 m
to the more
accurate name of Soil Temperature (TSOIL)
- Modify the precision of Relative Humidity
(RH) grids
- Modify GRIB encoding level of Total Cloud
Cover (TCDC),
removing
"considered as a single layer"
- Move Snow Depth (SNOD) from the *pgrb2b*
files into the
*pgrb2* files
New Products:
- Produce GRIB2 output at the highest
resolution on 0.25
degree
latitude-longitude grid 193 (1440x721)
gfs.YYYYMMDDCC/gfs.tCCz.pgrb2.0p25.FH
gfs.YYYYMMDDCC/gfs.tCCz.pgrb2b.0p25.FH
Product
Timeliness:
GFS product
delivery timing on NOMADS, the ftp server and
NOAAPORT will be
delayed for numerous products. Pressure
GRIB (*pgrb*) files will be as much as 20 minutes delayed.
Please reference
this page for a full list of delays:
http://www.nco.ncep.noaa.gov/pmb/changes/gfs_upgrade.shtml
NOAAPORT/SBN
product changes:
- Additional
forecast hours 186, 198, 210, 222, and 234 will
be added for the following GRIB2 grids only.
There are no
new headers to add as these grids use existing
headers:
201 - 381km
Northern Hemisphere
212 - 40km CONUS
213 - 95km CONUS
160 - 47.5km
Alaska
161 - 0.5 degree lat/lon for Puerto Rico
254 - 40km
Pacific Region
- Variables
averaged or accumulated over time, such as
precipitation, will now be valid over a 6 hour period
for forecast hours 180 through 240, rather than
a 12
hour period. There are no new headers to add as
these
new grids use existing headers.
4) Downstream
model impacts
There are impacts
to downstream GFS models and their product
output. Please reference this page for more
information on
the following:
http://www.nco.ncep.noaa.gov/pmb/changes/gfs_upgrade.shtml
- GFS-based Model
Output Statistics (MOS) products
- Global Ensemble
Forecast System variable change
- Numerous
downstream model output timeliness changes. These
changes impact both NOAAPORT/SBN and the NCEP/NWS
servers.
5) Parallel data
available
Due to system
constraints the parallel GFS will run on the
backup supercomputer. This will cause impact to
output
availability on at least 3 days due to mandatory
maintenance. We will notify users when a cycle will not
be
available through this user list:
https://lstsrv.ncep.noaa.gov/mailman/listinfo/ncep.list.nomads-ftpprd
Starting in late
October all parallel data sets will be
available on the following servers:
ftp://ftp.ncep.noaa.gov/pub/data/nccf/com/gfs/para/gfs.YYYYMMDDCC/
ftp://ftp.ncep.noaa.gov/pub/data/nccf/com/gfs/para/gdas.YYYYMMDD
http://www.ftp.ncep.noaa.gov/data/nccf/com/gfs/para/gfs.YYYYMMDDCC/
http://www.ftp.ncep.noaa.gov/data/nccf/com/gfs/para/gdas.YYYYMMDD/
NCEP has a full
list of products that will be available for
download from both the NCEP and NWS servers as well
as
NOMADS. You can find the file names and their
inventory
through the following http page:
http://www.nco.ncep.noaa.gov/pmb/products/gfs/index.shtml.up
grade
For more
information on this GFS upgrade, please see EMC
real-time and retrospective parallels and verification
pages:
http://www.emc.ncep.noaa.gov/gmb/wx24fy/vsdb/gfs2015/
http://www.emc.ncep.noaa.gov/gmb/wd20rt/
http://www.emc.ncep.noaa.gov/gmb/STATS_vsdb/
NCEP urges all
users to ensure their decoders can handle
changes in content order, changes in the scaling
factor
component within the product definition section (PDS)
of the
GRIB files, and volume changes. These elements may change
with future NCEP model implementations. NCEP will
make every
attempt to alert users to these changes before
implementation.
For questions
regarding these changes, please contact:
Mark Iredell
NCEP/Global Climate and Weather Modeling
Branch
College Park, MD
301-683-3739
For questions
regarding the data flow aspects of these data
sets, please contact:
Carissa Klemmer
NCEP/NCO Dataflow Team
College Park, MD
301-683-0567
ncep.list.pmb-dataflow@noaa.gov
NWS National
Technical Implementation Notices are online at:
http://www.nws.noaa.gov/os/notif.htm
$$