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Latent and Sensible heat flux

D

daloqail

New member
Hi
I have a question about the energy budget, latent and sensible heat fluxes. I run WRF for two times in the same location, the first run which is the original run has a lower roughness length and higher albedo, whereas the second run has a lower albedo and a higher roughness length. for the second run there was an increase in the net radiative flux and ground heat flux which in turn increase the sensible heat flux. But the thing that I can't understand that why the latent heat flux decreases! the bowen ratio for the first run was about 1 where as for the second run it was 3 which is a big difference between both of them.
The second concern that the energy budget (NOAH_LSM) doesn't close with me for both run (the residuals -1.2 w/m2), it's not balanced!!
This is how I calculate it:
gsw = (1-ALBEDO) * SWDOWN
glw = GLW
lwupflux = np.power(TSK,4) * STBOLT
netlw = EMISS*(glw-lwupflux)
netrad = gsw + netlw
seb = netrad + GRDFLX -HFX -LH

Please anyone can help!
 
Have you ever used the model output of GSW, GLW, GRDFLX, LH and HFX to calculate surface energy budget? What is the value of seb?
 
I am suspicious that this issue is related to albedo and emiss you used in the post-process. I will talk to our expert and let you know after they get back to me.
 
Hi, did you check the NOAHRES variable? This is the energy residual diagnostic output (WRF/phys/module_sf_noahdrv.F at master · wrf-model/WRF). The energy residual should be very small. Did you use the effective total surface emissivity? Also, in the second run, due to the higher surface roughness, the turbulent heat exchange coefficient will be smaller, which leads to a lower LH and SH. However, due to a lower albedo, the total energy driving SH and LH is increasing. If your point is a relatively dry soil point, then most of the increased absorbed radiation will go to SH to increase SH and then LH decrease is dominated by the effect of increased surface roughness length.
 
Thanks for you answer! The NOAHRES gave mostly the same as the energy budget equations! So, I think I calculate it correctly.
 
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