Difference between revisions of "Nesting Suite"

m (S.wales moved page U-aa753 Nested Suite to Nesting Suite)
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{{Needs Update}}
 
 
[[Category: Unified Model]]
 
[[Category: Unified Model]]
  
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* https://code.metoffice.gov.uk/trac/roses-u/ticket/52
 
* https://code.metoffice.gov.uk/trac/roses-u/ticket/52
  
==Nesting inside ERA-Interim==
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Job Ids on Gadi:
 
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- u-bm651: Copy of u-bi769 (UM vn11.4 suite), used for 2.2km nest of [[Aus400]]
The suite can be driven from ERA-Interim analyses with a small amount of setup.
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- u-cb265: Copy of u-bi769, set up for era5 boundary conditions
 
 
At NCI we have 6 hourly ERA-Interim analyses in GRIB format under the directory /g/data1/ub4/erai/grib. As ERA-Interim is under licence, make sure you comply with requirements [[ERA INTERIM | here]] before starting
 
 
 
Currently code changes required to run from ERA-Interim are in the job '''u-at264''', which is based on the 2017 nesting suite.
 
 
 
Make a copy of this job with
 
<syntaxhighlight lang=text>
 
rosie copy u-at264
 
</syntaxhighlight>
 
 
 
Open the job in `<span style="font-family:monospace">rose edit</span>` and make the following changes to '''suite conf''' to enable ERA-Interim driving:
 
* In 'General run options' make sure SITE is NCI
 
* In 'Driving model setup', set:
 
** 'dm_name' to 'ECMWF forecast fields'
 
** 'dm_ec_ic_lbc_dir' to '<span style="font-family:monospace">\$ROSE_DATA/erai</span>'
 
** 'dm_ec_cb_freq' to '21600' (6 hours, the ERA-Interim analysis frequency)
 
 
 
To run from ERA interim the suite needs to generate lateral boundary conditions from the ERA-interim GRIB files. To enable this you need to create a new 'Resolution setup' that is a bit larger than your coarsest LAM domain. This resolution won't be used to run the model, instead the ERA interim data will be interpolated to it so that the boundary conditions can be cut out for the LAM. For instance if your coarsest LAM is a 200x200 grid with resolution 0.1 x 0.1 degrees, a 220x220 grid at the same resolution would be fine - this gives a border of 10 grid points around each edge to use for the boundary conditions. You could also use less grid points at a coarser resolution, though be cautious as this adds an extra interpolation step.
 
 
 
You will need some extra ancillary files when using ERA-Interim, set the following in your new resolution, as well as your coarsest LAM resolution:
 
* vegsoil_anc: True
 
* lai_anc: True
 
* alb_anc: False
 
* orog_strm: False
 
* 3D_ancils: True
 
* sstsmc_anc: True
 
 
 
Set the `<span style="font-family:monospace">nmods</span>` to 0, since we just want the ancillaries at this resolution (this will print a warning in Rose, which can be ignored)
 
 
 
To make the ERA interim driver use this resolution you just set up, in the 'Driving model setup' page set '<span style="font-family:monospace">dm_ec_lam_ancil_dir}}' to the new resolution's ancillary directory. For instance, if the new resolution is `resn_2` of region `Regn1`, set `{{dm_ec_lam_ancil_dir}}` to `{{\$ROSE_DATA/ancils/Regn1/resn_2</span>`
 
 
 
Note that the resolution of the ERA Interim source dataset is ~ 0.75 x 0.75 degrees, keep this in mind when choosing the resolution of your coarsest LAM (i.e. make sure your LAM isn't inside a single ERA Interim grid point!).
 
 
 
https://code.metoffice.gov.uk/trac/rmed/wiki/suites/nesting/ECdriver
 
 
 
[[include component="page" wikiName="climate-cms" page="Index UM" editable="1"]]
 

Revision as of 23:19, 31 May 2021


Up-to-date information and news about the nested suite can be found on the RMED wiki and Rose issue tracker:

Job Ids on Gadi:

- u-bm651: Copy of u-bi769 (UM vn11.4 suite), used for 2.2km nest of Aus400
- u-cb265: Copy of u-bi769, set up for era5 boundary conditions