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Prescribing constant radiative cooling?

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Y

yhwong

New member
Hi,

I am trying to run an idealized Radiative-Convective Equilibrium (RCE) case in WRF SCM and would like to prescribe a constant radiative cooling (e.g. -1.5K/day). I am wondering how can I do that. I could set the namelist option for ra_lw_physics and ra_sw_physics to zero, which will disable the radiation schemes. However,

  • Where can I prescribe the constant radiative cooling rate? In the radiation driver module? or should this be done in a separate forcing file for the SCM?
  • If I switch off the schemes and prescribe radiative cooling, how would the other variables that are computed in the radiation scheme (e.g. GLW, OLR, top of atmosphere and surface fluxes) be computed then? I was using the RRTMG schemes.

Thanks a lot for any advice you could provide!
 
Do you know that WRF provides the idealized case for convective-radiative equilibrium (em_convrad)? Is there any special reason you want to run convective-radiative equilibrium tase using SCM?
 
Hi Ming,

Yes i know that WRF has a radiative convective equilibrium case, but that is not what I want. I want to use the SCM case and simulate RCE. And for my specific purposes I also need to prescribe a constant radiative cooling, could you advice?

thanks!
 
I looked at the issues you raised, and below are my suggestions how to do:

in radiation driver, you can specify the variable "rthraten" (i.e., use the specified value to replace the one WRF computes), which is the theta tendency caused by radiation.

you can still run SCM with the radiation scheme on, which will give you other variables like OLR, etc.

However, note that the specified value of rthraten might not be consistent with other radiative variables. And the model may crash due to the inconsistency.

Based on your case, you may also need to change other tendencies like RTHRATENLW, RTHRATENSW, etc.

Please let me know if this works or not.
 
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