Seeking description of momentum handling at model top

[ThomasH]

Hi all,
I'm a newer user working with data from the prescribed SST AMIP simulations, comparing elements between CAM6 runs and WACCM6 runs. I'm looking specifically for an explicit description of how momentum flux/deposition is handled at the model lid for each configuration. I've reviewed the user guides, their respective publications, and more general publications that cite the model(s). Still, I am having a hard time finding explicit language that goes beyond an allusion to momentum handling. Can anyone recommend a text resource, or is it more likely that I'll have to review the code?
Thanks so much for any information.

 

[islas]

I can't answer the question about all aspects of the momentum, such as the sponge layer. But for the gravity waves, what happens to the gravity wave momentum flux is controlled by tau_0_ubc. When tau_0_ubc is set to True, the gravity wave drag momentum flux is deposited at the model lid, when it's set to False it passes through. In CAM6, tau_0_ubc is False, so gravity wave momentum flux is not deposited at the model lid. I believe that's also true in WACCM6 although I'm less confident about that. But this is at least a parameter that you can check for in namelist settings to know what is being done with the gravity waves.