Real case WRF 1km turbulent flux

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satiz

New member
I have simulated a cold front in WRF at 1 km resolution and wanted to check the sub-grid scale turbulent momentum (u'w', v'w') and heat fluxes (q'w'). It appears to me that WRF doesn't output these fluxes. For that I have modify the modules to output these fluxes right? Or is there any option through namelist to output these. Since I have already ran the simulation I was thinking of approximates to these fluxes. But I would like to compare bot online and offline terms.
NOTE: I use WRF 4.3.3 and output is already saved at 5-min interval.
 
Hi, You are correct that these subgrid fluxes are not output by WRF, unfortunately. If you haven't seen this thread already, it may be somewhat useful to you.
 
Thanks, Kelly for sharing the thread. I have gone through that thread, and it appears that I can just output the exchange coefficients for momentum and heat with which I can compute the turbulent momentum (u'w', v'w') and heat fluxes (q'w'). For this, Flux = K*dF/dS (F- u,v,q;S-x,y,z) should be used right. Since I use MYNN PBL scheme, I have to modify these modules alone right?
 
kwerner said:
Hi, You are correct that these subgrid fluxes are not output by WRF, unfortunately. If you haven't seen this thread already, it may be somewhat useful to you.
Click to expand...
I checked into the MYNN PBL scheme and figured out a way to estimate u'w', v'w' and T'w' using terms of TKE. Could you please confirm if this is a right approach. It seems to be mathematically correct for me.
 

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satiz said:
I checked into the MYNN PBL scheme and figured out a way to estimate u'w', v'w' and T'w' using terms of TKE. Could you please confirm if this is a right approach. It seems to be mathematically correct for me.
Click to expand...
Can anyone confirm this???? Actually I compared it with a single run and it turns out that the correlation between fluxes directly output by model and reconstructed with equations is 0.99!!! Seems pretty good for me!!
 
Hi, apologies for the delay in response. I was out of the office recently and am getting caught up now. It sounds like you're on the right track, and the reconstruction with the equations should make you confident in your method. There will always be a small amount of residual, so a 99% outcome is reasonable. I would recommend continuing with your process and just do some occasional checks to make sure the results aren't unreasonable.
 
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