Introduction to the EMC pre-implementation
GFS/CFS parallel system
Shrinivas Moorthi
EMC GFS/CFS parallel jobs are run just like the NCEP
operational jobs
However, SMS used in the NCEP operations is not used
The EMC parallel includes a global data assimilation cycle
which involves assimilation of observations over a 6 hour
window using a first guess from a 9 hour global forecast from a
previous analysis. This is known as “gdas” cycle.
Operational forecasts of 384 hours are made from a global
analysis made with partial observations because of forecast
window. This is known as “gfs” cycle
Forecasts made from “gdas” analysis could be superior to that
from a “gfs” analysis – CFSV2 forecasts are made from gdas
cycle.
GFS/CFS scripts are very general
Can be used to make just the “gdas” analysis
Can be used to just make forecasts with given
initial conditions
Can be used to make coupled analysis or just the
coupled forecast when the initial conditions are
available.
Both the original global_post as well as the
unified nceppost options are available.
3D diagnostic output is also possible for physics
tendencies – nceppost posts 3D diagnostics
VSDB verification package is available
For long forecasts, options to write out monthly
means and to extract time-series of selected
variables is also available.
GFS/CFS Parallel System
Structure
para
bin
ncpx ptsr
psub pmkr
plog perr
pend pcop
pcon pcne
pbeg pavg
pend
exec
Executables
exp
fix
jobs
parms
scripts
ush
util
vsdb
para_config
submit.sh
rlist
crtm_2.0.2
fix_am
fix_gsi
fix_lm
fix_om
fix_vsdb
anal.sh angu.sh
arch.sh avrg.sh
copy.sh d3dp.sh
dcop.sh dump.sh
fcst.sh g3dp.sh
lanl.sh oanl.sh
ocnp.sh post.sh
tavg.sh vrfy.sh
etc
parm_am
parm_lm
parm_om
parm_prep
many
scripts
many
shell
scripts
many utility
shell
scripts
VSDB
package
Users mostly have to create a “config” file like the file “para_config”
in the “exp” directory.
The name “config” could be anything and could be located anywhere
on the computer
Jobs are submitted using the “psub” command residing in the “bin”
directory.
This command needs four arguments - “config”, “cdump”, “cdate”
and “step”
“cdump” refers to the data dump where “gdas” is for the complete
data dump and “gfs” is the data dump with early cutoff.
Jobs can be submitted from any step
In NCEP operations we run GFS forecasts with two resolutions A T574 forecast up to 192 hours and then aT384 forecast up to 384
hours.
EMC parallel scripts can therefore run two segments
(A three segment option is available, but not updated at this time)
Some of the available steps are
prep
anal
oanl
lanl
fcst1(2)
post1(2)
vrfy1(2)
arch
- data preparation step
- data assimilation using GSI
- Ocean analysis using godas
- Land analysis using GLDAS
- first (second) segment forecast GFS/CFS
- first (second) segment post
- first (second) segment verification
- step for data archival
CFS parallel Scripts
Start here
Copy IC files
copy.sh
Prep step
Hurricane relocation
Data preparation
prep.sh
AM and OM
Post
post.sh
9 hr Coupled Model
Forecast (first guess)
GFS + MOM4 with Sea Ice
MPI-level Coupling
fcst.sh
Expt
website
GODAS
Global Ocean Data
Assimilation
oanl.sh
Seasonal
Forecast?
Time 00Z ?
GLDAS
Global Land
Data Assimilation
lanl.sh
GDAS
Global Atmospheric
Data Assimilation
GSI
anal.sh
Run seasonal
Forecast
fcst.sh
Verify
vrfy.sh
Archive
data
arch.sh
NCEP’s UNIFIED POST
PROCESSOR (UPP)
•Hui-Ya Chuang
• The Unified post Introduction
(UPP) was developed as the
common post processor for GFS, CFS, NAM, and
WRF ARW.
• The use of a common post ensures that all model
outputs at EMC are processed and verified the same
way.
• UPP reads in model output in binary, GRIB, or
netCDF format, and then generates output in GRIB.
Functions and features of UPP
Functions and features of UPP
• Performs vertical interpolations onto isobaric and
other non-model surfaces
• Computes diagnostic fields
• Destaggers wind onto mass points (WRF ARW)
• An MPI-parallel code
Fields generated by the UPP
•
The UPP currently outputs 507 fields.
– Complete list in the subroutine RQSTFLD
•
Sample fields generated by UPP:
1) T, Z, humidity, wind, cloud water, cloud ice, rain,
and snow on isobaric levels
2) Shelter level T, humidity, and wind fields
3) SLP (two kinds)
4) Precipitation-related fields
•
Fields generated by the UPP
Sample fields generated by UPP (cont.):
1) PBL-related fields
2) Diagnostic fields (e.g., simulated radar
reflectivity and simulated satellite brightness
temperature)
3) Radiation fluxes
4) Surface fluxes
5) Cloud related fields
6) Aviation products
Computation of isobaric fields

Vertical interpolation of all state fields from model
to pressure levels is performed in linear in ln(p)
•
Underground vertical and horizontal wind components
are specified to be the same as those at the first
atmospheric model layer above ground.
•
Underground temperature is reduced by assuming
constant virtual potential temperature from the
temperature averaged over the second and the third
model levels above the surface.
Derivation of sea level pressure type I:
standard NCEP SLP
• Ground and sea level temperatures are extrapolated from the
temperature at the lowest atmospheric layer by assuming a
constant lapse rate of 6.5 K/KM.
• Compute   Rd Tv / g at ground and sea level and then apply
Shuell correction to both s. The basic principal of Shuell
correction is to make sure that s at both sea level and
ground do not exceed a critical value.
• Standard NCEP SLP is then derived as follows:
SLP  PSFC  exp(
2  HSFC
)
 ( SFC )   ( SLP)
Derivation of sea level pressure type II:
membrane NCEP SLP

Re-compute underground virtual temperatures by
horizontally relaxing virtual temperatures on pressure
levels:
 2Tv  0.


The nine-point successive over-relaxation formula is used
to solve the above Laplace’s Eq. numerically.
Once all underground virtual temperatures are generated,
the hydrostatic equation is integrated downward to obtain
sea level pressure.
Running UPP
•UPP needs three input files to run:
– itag: four-line file specifying details of WRF output to
process
– wrf_cntrl.parm: control file specifying fields to output
– eta_micro_lookup.dat: look-up table for Ferrier MP
•In the sample scripts, these three files are generated on the fly or
automatically linked.
Outputting fields on multiple levels
• UPP outputs fields on several vertical coordinates:
– Native model levels
– 47 default isobaric levels: 2, 5, 7, 10, 20, 30, 50, 70 hPa,
then 75 to 1000 hPa every 25 hPa
– 7 flight levels above MSL: 914, 1524, 1829, 2134, 2743,
3658, and 6000 m.
– 6 PBL layers (values averaged over 30 hPa thick layers)
– 2 AGL levels: 1000 m and 4000 m for radar reflectivity.
Examples
•
Output T every 50 hPa from 50 hPa to 1000 hPa:
(TEMP ON PRESS SFCS
) SCAL=( 3.0)
L=(00000 01001 01010 10101 01010 10101 01010 10101 01010 10000 00000…)
From left to right, the isobaric levels go 2,5,7,10,20,30,50,70
then 75-1000 hPa every 25 hPa.
•
To output instantaneous surface sensible heat flux:
SFC SENHEAT FX ) SCAL=( 3.0)
L=(10000 00000 00000 00000 00000 00000 00000 00000 0000(INST 0 00000 00000…)
•
To turn off cloud top height:
(CLOUD TOP HEIGHT
) SCAL=( 3.0)
L=(00000 00000 00000 00000 00000 00000 00000 00000 00000 00000 00000…)
UPP control file
GRIB packing
precision
•
•
(PRESS ON MDL SFCS ) SCAL=(6.0)
L=(11000 00000 00000 00000 00000 00000 00000 00000
00000
•
(HEIGHT ON MDL SFCS ) SCAL=(6.0)
•
L=(11000 00000 00000 00000 00000 00000 00000 00000
00000
code keys on these
character strings. Product
description – post
•
“1” = yes, “0” = no
Except for AGL and isobaric levels, vertical levels are counted from the ground
surface up in gfs_cntrl.parm.
•
Examples
Output T every 50 hPa from 50 hPa to 1000 hPa:
(TEMP ON PRESS SFCS ) SCAL=( 3.0)
L=(00000 01001 01010 10101 01010 10101 01010 10101 01010 10000 00000…)
From left to right, the isobaric levels go 2,5,7,10,20,30,50,70
then 75-1000 hPa every 25 hPa.
•
To output instantaneous surface sensible heat flux:
SFC SENHEAT FX ) SCAL=( 3.0)
L=(10000 00000 00000 00000 00000 00000 00000 00000 0000(INST 0 00000 00000…)
•
To turn off cloud top height:
(CLOUD TOP HEIGHT ) SCAL=( 3.0)
L=(00000 00000 00000 00000 00000 00000 00000 00000 00000 00000 00000…)
Sample Diagnostic fields
Precipitation and derived Radar reflectivity
Sample Diagnostic fields
Observed and derived GOES water vapor Ch
observed water vapor ch
simulated water vapor ch