d02 appears in plot of d01 for rainfall

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jbasconcillo

New member
i have 2 domains when I simulated WRF. When I plotted the rainfall in D01, it looked there is a cavity from D02. Is this how it really supposed to look like? I mean, the plot of D01. It doesn't appear like it is supposed to be that way. Any thoughts, please?
 

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kwerner

Administrator
Staff member
HI,
1) Is the variable you're plotting RAINC?
2) Do you have cu_physics turned off for the inner domain?
3) Do you have feedback turned on?

If so, then this is a normal result, and not an error. RAINC in the WRF model is only produced when a cumulus scheme is turned on. Since there is no cumulus scheme for d02, and feedback is turned on, the values of RAINC for d02 (which should be zero) overwrite the values of those points in d01. This is perfectly fine, and is what we would expect to see. Most people are not necessarily interested in the results for d01 when they are nesting. They only use d01 as a segway to ensure smooth results to the domain of interest, which is the nest. So the point is that this is perfectly normal and fine.

If the answer to the questions above are "no" for any of them, please send your namelist.input and let me know which version of WRF you are using. Thanks!

(Note: I've modified the title of this thread to more specifically describe the issue.)
 

jbasconcillo

New member
Thank you for the reply.

1) Is the variable you're plotting RAINC? Yes, I plotted RAINC here.
2) Do you have cu_physics turned off for the inner domain? Yes, the cu_physics is turned off.
3) Do you have feedback turned on? Yes, the feedback is turned on.

I am interested in d01 but I am thinking that since it is a two-way feedback, the higher resolution of d02 will improve the performance of d01. What do you suggest I should do?
 

kwerner

Administrator
Staff member
The feedback option will only feed back data from the points in d02 to the corresponding points in d01, so the feedback from a higher resolution is only having an advantage in the area of d02. I would recommend determining the exact domain you are interested in, and make that your higher-resolution domain. You can use a larger and coarser outer domain as a buffer around the domain of interest, if needed. In case you're interested, here are a couple of best practice pages that can help you. The WPS page, especially, helps with setting up the domain.
https://www2.mmm.ucar.edu/wrf/users/namelist_best_prac_wps.html
https://www2.mmm.ucar.edu/wrf/users/namelist_best_prac_wrf.html

And you can obtain additional information about nesting from this presentation.
 
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