http:// this is the footer running wrf on hector ralph burton, ncas (leeds) alan gadian, ncas...
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http://www.ncas.ac.ukThis is the footer
Running WRF on HECToR
Ralph Burton, NCAS (Leeds)Alan Gadian, NCAS (Leeds)
With thanks to Paul Connolly, Hector support team
http://www.ncas.ac.uk
WRFV2 flow chart
http://www.ncas.ac.uk
WRF: Overview
Decide upon which domain you wish to use*
Acquire some met. data for the dates you are interested in
Run the WPS
Run WRF
Examine the output
Stages in running WRF
* only need to do this once
http://www.ncas.ac.uk
Decide upon which domain you wish to use*
Acquire some met. data for the dates you are interested in
Run the WPS
Run WRF
Examine the output
Stages in running WRF
* only need to do this once
http://www.ncas.ac.uk
Determining your domain
Either compute manually and enter your valuesinto the WRF input files (see later) [ harder ]
or
Use the WRFDomainWizard [ easier ]
Where do I want my grid? What resolution do I need? How many nests do I want?
http://www.ncas.ac.uk
Determining your domain: WRF domain wizard
http://www.ncas.ac.uk
Decide upon which domain you wish to use*
Acquire some met. data for the dates you are interested in
Run the WPS
Run WRF
Examine the output
Stages in running WRF
* only need to do this once
http://www.ncas.ac.uk
Acquire some met data (forecast files)
GRIB data is online
Usually the 06Z forecast cycledata is available in the UK mid-afternoon
Online:April 21st 2007 – present
Offline: Feb 15th 2005 – April 20th 2007
http://www.ncas.ac.uk
Acquire some met data (forecast files)
Download (FTP) the files from the NOMADS web site:
Frequency of GRIB data varies, but for 1-degree GFS forecast we have
4 cycles / day : 0Z, 6Z, 12Z, 18Z
Forecast hours: analysis, T+3, T+6, ..., T+180
Download speed varies, but each GRIB file (~20Mb)takes ~ 3 minutes
Do this stage some time before you need to do the run
http://www.ncas.ac.uk
Decide upon which domain you wish to use*
Acquire some met. data for the dates you are interested in
Run the WPS
Run WRF
Examine the output
Stages in running WRF
* only need to do this once
http://www.ncas.ac.uk
WPS: Pre-processing
Edit the “namelist.wps” file
This file contains informationabout:
Start and end times
Grid definition
Location of the ancillaryfiles (land use, orography, etc
http://www.ncas.ac.uk
WPS: Pre-processing
WRF Pre-processing system (WPS)
geogrid.exe
ungrib.exe
metgrid.exe
Computes the grid formulation for your run
Extracts the met. data from your input (GRIB) files
Interpolates the met. data onto your grid (defined above)
http://www.ncas.ac.uk
Decide upon which domain you wish to use*
Acquire some met. data for the dates you are interested in
Run the WPS
Run WRF
Examine the output
Stages in running WRF
* only need to do this once
http://www.ncas.ac.uk
Running WRF
Edit the “namelist.input” file
Start and end times
http://www.ncas.ac.uk
Running WRF
Edit the “namelist.input” file
Time step andgrid definition
http://www.ncas.ac.uk
Running WRF
Edit the “namelist.input” file
Microphysics; surface layer;boundary layer
http://www.ncas.ac.uk
Running WRF
Edit the “namelist.input” file
Dynamicsoptions
http://www.ncas.ac.uk
Running WRF
real.exe
wrf.exe
For each WRF run, two separate executables need to be run.
these are already compiled; independent of choiceof grid, number of processors requested, microphysicsschemes, timestep, etc etc.
real.exe takes minutes and is run on a few processors. It sets up the input files required by WRF proper.
wrf.exe is the main body of the code
http://www.ncas.ac.uk
Running WRF
Standard scripts exist for submitting real.exe and wrf.exe
e.g. wrf_exe.sh
no need to alteranything belowhere
This will request 512 dual-corepreocessors; 12 hours wallclocktime
http://www.ncas.ac.uk
Running WRF
Submit the jobs to the queue
qsub real_exe.sh
then
qsub wrf_exe.sh
... and that’s it!
A 60 hour, 3 domain (9 - 3 – 1 km) 60 hr forecast for the UK, output filesevery hour, including 2 restart files takes ~10 hours using 512 dual coreprocessors.
http://www.ncas.ac.uk
Decide upon which domain you wish to use*
Acquire some met. data for the dates you are interested in
Run the WPS
Run WRF
Examine the output
Stages in running WRF
* only need to do this once
http://www.ncas.ac.uk
Examining the output
WRF output files are enormous (WRF UK output data ~60Gb)
One output file per nest; netCDF format
Post processing and looking at the output:
IDV – Interactive Data ViewerRIP and RIP4GrADSVis5DMatlabwrfpost
... generic netCDF viewers
http://www.ncas.ac.uk
Summary
In short, this is all you need to do:
geogrid.exeungrib.exemetgrid.exeqsub real_exe.shqsub wrf_exe.sh
Operation Operator effort
Hector effort
Download GRIB files
5 mins 40 mins
Edit namelist files
2 mins
Run WPS and WRF
5 mins 10 hours
http://www.ncas.ac.uk
Further info
WRF on Hector: full details and examples of UK forecast runshttp://ncasweb.leeds.ac.uk/weather
WRF on Hector: UK forecast runs