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The model does not detect all the water bodies

L

llsalazardom

Member
Hello,

I ran WRF with two domains at 3 km and 1 km resolution. However, the temperature results at 2 meters did not take into account all the water bodies in the region. I checked the landmask variable, and the model only recognizes two water bodies, while the region actually has many more rivers and ponds. How can I make the model detect all the water bodies?


The region is around Strasbourg. The only water bodies recognized are Étang SCHOTT and Étang Bohrie. However, Étang Gering, which is nearby, is not included in the landmask, nor are some other nearby ponds.


Could anyone please help me with this issue? Thank you

I'm attaching the namelist.input file
 

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  • namelist.input
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I am suspicious that the water bodies (e.g., river, pond, etc.) are too small for the model to resolve. if you look at your geo_em files, can you see these small-size water bodies?
 
Hi, thanks for your reply.

No, I see the same water bodies in the geo_em* files as in the wrfout* files. I'm attaching the geo_em.d02 file.
Could this issue be caused by the parameterizations?
 

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  • geo_em.d02.txt
    2 MB · Views: 2
It is expected that water body should be same in geo_em and wrfout files. This confirms that those small water bodies like rivers and ponds are not resolved in your case.
 
This is a multifaced problem by the combination of landmask, landuse, grid distance and interpolation type used by geogrid in order to produce final estimation of the surface type. You have 1000 m dx/dy, and 2 water bodies that are significantly smaller than that are "resolved" by geogrid (which is somewhat unexpected but it is a big question how they are represented in source data) and larger one that has diameter approx 850 m is not (that is actually expected).

What you will need in order to be sure that they are correctly represented in your static domain data:
1) find better resolution input data, like Corine land use, and I'm not sure if that will change things but it can't make it worse, better elevation data like ASTER, instead of what is offered in official WPS static fields repo for download
2) use much finer grid distance (approx 100m to resolve these small lakes correctly)
3) optionally, play with interpolation options in GEOGRID.TBL

I hope this helps!
 
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