Running the GFS Parallel System

Hybrid GSI/EnKF on Zeus

NOAA/NWS/NCEP/EMC

2

This presentation contains…

1. Overview of Hybrid GDAS structure

2. Running an experiment on Zeus w/ Hybrid (DEMO) New variables in configuration file New model input Submitting jobs with the Hybrid EnKF New model output

3. Suggestions for running experiments with the Hybrid EnKF

Documentation & Help

Website: http://www.emc.ncep.noaa.gov/GFS/exp.php

Listserv (Glopara Support):

NCEP.List.EMC.Glopara-Support@noaa.gov

In Person:

Stop by my cube next to the 2nd floor breakroom, I don’t bite

3

What’s hybrid in the hybrid GDAS?Augment fixed background error with

information from ensemble forecastsBenefits:

Improve forecastsmid-latitude mass fields tropical winds fits to observationscool season CONUS precipitation

Hybrid Var-EnKF

4

yxHRyxH

xBxx

1T

1f

T

3DVAR

2

12

1

J

fit to background

fit to obs

N

1n

ne

nft

t1T

t

N

1n

n1Tnef

1f

Tff

f

,

2

1

2

1β

2

1β

,J

xxxwhere

yxHRyxH

LxBxx

α

ααα

fit to bkg

fit to obs

ens fcst

5

6

prep

GDAS Hybrid Var-EnKF Flow Chartanal

eobs eomn

eomg01

eomg02

eomg03

eomg04

eomg05

eomg06

eomg07

eomg08

eomg09

eomg10

eupd ecen efmn

efcs01

efcs02

efcs03

efcs04

efcs05

efcs06

efcs07

efcs08

efcs09

efcs10

epos

fcst post

echk echkarch

earc

angu

vrfy

EnKF job steps (start to update)

echk check file availability

eobs select observations used in

ensemble innovations

eomn submit and monitor

ensemble innovation jobs

eomg01,…, eomg10 compute ensemble

innovations (8 members/job)

eupd compute ensemble analyses

(EnKF update code)

7

EnKF job steps (re-center to archive)

ecen recenter ensemble analyses

about hires analysis

efmn submit and monitor

ensemble forecast jobs

efcs01,…, efcs10 run ens fcst (8 members/job)

epos compute ensemble mean spectrally smooth ens fcst

earc save data & cleanup

8

WARNING!!!

Hybrid GDAS generates a LOT of output80 member T254L64 ensemble

1316 files / cycle90.8 Gbytes / cycle

9

Alternatives

Ask yourself - Do I really need to run hybrid GDAS?Can I use a lower resolution?

T382 hires, T190 ensembleT254 hires, T126 ensemble

Can I just run the GFS long forecast?Use ICs from Hybrid EnKF control runs

10

11

GFS Hybrid EnKF Experiment (DEMO)

1. New variables in configuration file

2. New model input

3. Submitting jobs with the Hybrid EnKF

4. New model output

Demo matches Zeus control prhy2s:

/NCEPDEV/hpssuser/g01/wx24kh/Zeus/para_gfs/prhy2s

Demo time…

Needed files:

Config file & rlist:

/scratch2/portfolios/NCEPDEV/global/save/Kate.Howard/TUTORIAL/prhy2s

Input/output in COMROT:

/scratch2/portfolios/NCEPDEV/global/noscrub/Kate.Howard/TUTORIAL/prhy2s

12

Demo time…

Experiment prhy2s:CDATE = 2012072512CDUMP = gdasCSTEP = fcst1gfs_cyc = 1 (run only 00z GFS)DOENKF & DOHYBVAR = YES (Hybrid EnKF DA)

EDATE = 2012072600EDUMP = gdasESTEP = prep

13

Configuration File – New Variables

To turn the Hybrid EnKF on:

DOHYBVAR=YESTells analysis to use ensemble product

DOENKF=YESTurns on ensemble process scripts

14

15

Initial Conditions in $COMROT

Acquire initial condition files and place in $COMROT:

1. biascr.$CDUMP.$CDATE2. satang.$CDUMP.$CDATE3. sfcanl.$CDUMP.$CDATE4. siganl.$CDUMP.$CDATE5. sfcanl_$CDATE_mem$MEM ($MEM = member # 1-80)

6. siganl_$CDATE_mem$MEM

Where do I find Hybrid EnKF ICs?

16

Where to find ICs

Places to acquire Hybrid EnKF control ICs for Zeus:

prhy2s - Summer 2012 control (July – September)

HPSS: /NCEPDEV/hpssuser/g01/wx24kh/Zeus/para_gfs/prhy2s

Tutorial input

HPSS: /NCEPDEV/hpssuser/g01/wx24kh/Zeus/TUTORIAL/prhy2s

17

Submitting the GFS w/ Hybrid EnKF

While in $EXPDIR, using the psub script from config file, type the following on the command line:

$PSUB $CONFIG $CDATE gdas fcst1$PSUB $CONFIG $CDATE gdas efmn

prep anal

eobs eomn

eomg##

eupd ecen efmn

efcs##

epos

fcst post

echk echkarch

earc

angu

vrfy

GFS Output - Dayfiles

Text output files containing details of run, as well as error messages for troubleshooting, found in $COMROT

Naming convention:

$PSLOT$CDATE$CDUMP$CSTEP.dayfile

New Hybrid EnKF CSTEPs:

18

• echk*• eobs• eomn• eomg##• eupd

• ecen• efmn• efcs##• epos• earc

* echk = epre

GFS Output – New Hybrid EnKF Data

19

http://www.emc.ncep.noaa.gov/GFS/exp.php#All_files

Documentation & Help

Website: http://www.emc.ncep.noaa.gov/GFS/exp.php

Listserv (Glopara Support):

NCEP.List.EMC.Glopara-Support@noaa.gov

In Person:

Stop by my cube next to the 2nd floor breakroom

20

Questions?

21