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WRF & WPS seasonal forecasting

K

kcmonaka

New member
Dear colleagues..

I have average knowledge on WRF and i intend to use it in our organization (Botswana Department of Meteorological Services) to produce seasonal forecast. The seasonal forecast will be purely focused on two parameters (Precipitation and temperature). Usually our rainfall season starts in November and overlaps into the following year around April. The models which are used is Climate prediction tool and Climate forecasting tool.

I need guidance as to how i must perform this task. I have been able to install and configure WRF & WPS. everything appears to have been configured and compiled correctly. the remaining task is now to produce a seasonal forecast.

Kindly assist.

Many thanks
 

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  • metgrid.png
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Hi,
When using WRF for seasonal forecast, the most important issue is that you need to turn on sst_update. All other options can be the same as "standard' WRF runs for short-term weather forecast. You also decide what forcing data you will use. Try to find the global analysis/reanalysis data that can well describe the weather/climate of the region you are interested. Also, higher resolution data could be better than lower resolution data. .
 
Thanks for the quick response. where is this "sst_update" located. will try identify reanalysis data that describes the climate of my region.

Thanks once again
 
sst_update is a nmaelist option specified in &physics.
By the way, please take a look at the file 'WRF/run/README.namelist', which provides all options and a brief description of these options. I suppose this file is helpful for new users to get familiar with physics/dynamics options of WRF.
 
Hello,
I have been trying to run a WRF simulation with CFS data to do seasonal dynamical downscaling.
In WRF CFSR Vtable there is information about the input needed files, but it only talks about CDAS files and I want to use CFSv2 operational runs which are 6-hourly. These contain data split into multiple files: pgrb, flx, ocn,... I'm not sure which files I should use.
Thanks
 
Ming Chen said:
if you download CFS data from NCAR RDA website, please take a look at the document here:

This document describes in detail the file name convention and variables included.
Click to expand...
Thanks for the documentation. However I see that these CDAS files only contain 9 hours of forecast. I want to use operational forecast CFS which hast 6-hourly data up to 9 months since I want to run a seasonal forecast.
 
Dear Collegues, I am still strugling to produce a simulation. My objective is to produce seasonal forecasts using WRF and WPS, i ran a test simulation just to see if i can produce a simple hindcast. I was able to configure WPS namelist and all programs were able to run but am struggling with the namelist for WRF.
Can i at least have a reference namelist which i can work on so that i am able to produce a seasonal forecast. or at least a reference book, paper i can read to help in archiving this objective?

Thank you
 

Attachments

  • namelist.input
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  • namelist.wps
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seasonal forecast using WRF is basically the same as that for weather forecast, except that the sst_update option must be turned on. This option will update sst, lai, seaice, greenfrac etc to ensure that surface information are time-varying over longer integration period.

I have modified your names.input and it should serve as an example how to run a seaonal simulation over 6-month period. However, note that the model domain, grid interval, physics options etc must be selected based on your case.

Hope this is helpful for you.
 

Attachments

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Good Day colleagues, attached is the namelist.input for seasonal forecasting. I did as suggested now I have an error attached below:

(ncl_stable) wrf@met-wr-bw:~/Build_WRF/WRF/run$ tail rsl.error.0000
ims,ime,jms,jme -4 120 -4 72
ips,ipe,jps,jpe 1 113 1 65
*************************************
DYNAMICS OPTION: Eulerian Mass Coordinate
alloc_space_field: domain 1 , 330562296 bytes allocated
-------------- FATAL CALLED ---------------
FATAL CALLED FROM FILE: <stdin> LINE: 409
error opening met_em.d01.2022-12-25_12:00:00.nc for input; bad date in namelist or file not in directory
-------------------------------------------
Abort(1) on node 0 (rank 0 in comm 0): application called MPI_Abort(MPI_COMM_WORLD, 1) - process 0

I tried running namelist.wps and i had errors since the gfs files i have are only for 48 hours (25 and 26 December 2022) there is something am missing please help.
 

Attachments

  • namelist.input
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@kcmonaka
Please check whether the file "met_em.d01.2022-12-25_12:00:00.nc" is available in your working directory.
The error message indicates this file is missing.
 
I tried running namelist.WPS with the dates going into 2023 but I encountered an error because my gfs files are just for 2 days (I.e. 25 and 26 December 2022). My question now is that do I need the gfs files for the entire forecast period?? But thinking about it in hindsight I think I need to download the gfs files.

My issue is that the gfs files are too big and to run for 3months or 6months (which I intend to do) I need to download the data from the global models then downscale with a regional model. It’s starting to make sense. Do you have a suggestion for datasets which are light in size??

https://ftp.ncep.noaa.gov/data/nccf/com/gfs/prod/gfs.20230201/00/atmos/gfs.t00z.pgrb2.0p25.f000. This one’s the file size is too big.

Thanks
 
You need all the GFS files for the period you intend to run WRF over.
Unfortunately there is no way to reduce the file size downloaded from the web.
 
kcmonaka said:
Dear colleagues..

I have average knowledge on WRF and i intend to use it in our organization (Botswana Department of Meteorological Services) to produce seasonal forecast. The seasonal forecast will be purely focused on two parameters (Precipitation and temperature). Usually our rainfall season starts in November and overlaps into the following year around April. The models which are used is Climate prediction tool and Climate forecasting tool.

I need guidance as to how i must perform this task. I have been able to install and configure WRF & WPS. everything appears to have been configured and compiled correctly. the remaining task is now to produce a seasonal forecast.

Kindly assist.

Many thanks
Click to expand...
Do you still need support on running WRF model for seasonal forecasts applications based on CFS data?
 
Yes please. i still need help. I have been keeping myself busy with simple real time simulations and currently stuck at data processing. i am failing to understand how RAINC and RAINNC work. soo playing through ncl and python codes and its challenging
 
Alright!

You need to do the following:

1. Download CFSV2 data for your season of interest. I normally do a 3 months and 6 months model runs for seasonal outlook applications.

These data are stored separately for surface data (flx) and variables at pressure levels (pgb).

It is recommended to download them into two separate directories like PRESS for variables at pressure levels data and FLX for variables at the surface.

Here is the link to those data Index of /pub/data/nccf/com/cfs/prod

I normally use 6 hourly grib1 files


2. You have different data so you should ungrib those data twice.

Here are the lines in the namelist.wps which you should have

&ungrib
out_format = 'WPS',
!prefix = 'FLX',
!prefix = 'PRES',

Here both have been commented by !

&metgrid
io_form_metgrid = 2,
fg_name = 'FLX','PRES',



Step 1: Ungrib any data say we start with FLX. This is normaly very fast because we have less variables

First, un-comment by removing the ! in the &ungrib for FLX, section and also link the correct Vtable

ln -sf Variable_Tables/Vtable.CFSR_sfc_flxf06 Vtable

Remember to link the correct data with ./link_grib.csh PATH TO YOUR FLX DATA

Run ungrib

Step 2: Run ungrib for PRES data, normally it takes some minutes depending on the length of the season and your domain size

Comment the line for FLX and un-comment the one for PRES in the section of &ungrib

link the correct Vtable for data at pressure levels

ln -sf Variable_Tables/Vtable.CFSR_press_pgbh06 Vtable

Remember to link the correct data with ./link_grib.csh PATH TO YOUR PRES DATA

Run ungrib

After step 1 and 2 have been successfully completed now proceed with metgrid and wrf part as you normally do.

I suggest you to first do it step by step and later you can automate the process after all the steps have been clear to you.

Drop a message if these steps work for you or incase of any challenges and you need more clarification
 
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