Prescribing warming tendency?

[yhwong]

Hello,

I am running an idealised simulation using WRF single column model. I would like to perturb the model with an additional warming tendency (i.e. dT/dt, in units K s-1) and am not sure what is the best way to do it. From what I understood, WRF has individual warming tendency for the schemes, e.g. RTHCUTEN for cumulus scheme, RTHBLTEN for PBL scheme, etc. And then the model adds up all these tendencies. My questions are:

• How do I add an additional warming tendency? Do I have to add it to one of the existing variables (e.g. to RTHBLTEN)? For example, RTHBLTEN = RTHBLTEN_from_pbl_scheme + RTHBLTEN_prescribe?

• Would that affect the behaviour of the PBL scheme if I do so?

• Is there a "cleaner" way to do it, for example by adding the additional warming tendency as a new variable? Since the tendencies are eventually added up anyway. But I suspect this might require changing a lot of the code?

Thank you very much for any insight or advice you can provide!

 

[Ming Chen]

The straightforward way to add an artificial warming tendency is to add it to an already-existing tendency term, as shown in your email.
THE PBL process will be affected if you add an extra warming tendency, since it will affect the prognostic variables like T, GHT, etc.
I don't think you can add extra variables to the model system without modifying the codes. You are right that this will involve any changes of codes.