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geog_data_res on a 9km and 2.5km WRF simulation

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L

lquitian

Member
Good morning,

I would like to run a simulation with a mother domain of 9km and little domain of 2.5km horizontal resolution and I would need to know which values should I specify on the geog_data_res variable of the namelist.wps file. As far as I understand, with this variable, you specify the resolution for the interpolation of the terrain data.

I have read that this variable only affects the WRF geogrid pre-processing. In other words, it's independent of my simulation resolution. Is this correct?

Moreover, I would like to know if this variable affects the interpolation of the initial surface conditions, that is, how the geogrid variables are assumed by the WRF metgrid.

Thanks in advance.
Kind regards,

Lara
 
For nesting case, the ratio of parent-child domain must be integer (e.g, 3, 5, etc). If your parent domain resolution is 9km, then the resolution in child domain should be 3km instead of 2.5km.

The default option of WPS for static data should be fine for your case. Please set geog_data_res = 'default','default' in your namelist.wps.

Static variables from the GEOGRID will be read into met-em file, and then used for vertical interpolation and some fields adjustment in REAL program. They do affect the initial condition of the model.
 
Thank you so much!

Just one more thing: what do you mean by static data? That the moving-nest option is not active? I usually work with the moving-nest compilation. I should have told you. Sorry about that.

Sincerely,
Lara
 
Static refers to the data located at WPS_GEOG (specified by geog_data_path in namelist.wps). These data include terrain, land use type, lai, monthly albedo. etc.
 
OK! Thanks!

I 'm sorry, but I have another couple of questions thereon. How can I know when to use the default option and not a specific value (10m, 5m, 30s, etc.).
And if I use the default option, how can I know which resolution is the model using?

Thanks in advance.
Lara
 
Please take a look at the file WPS/geogrid/GEOGRID.TBL, in which you will find default option for individual input data. More information can be found in
http://www2.mmm.ucar.edu/wrf/users/docs/user_guide_v4/v4.0/users_guide_chap3.html#_Description_of_GEOGRID.TBL
 
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