[MITgcm-support] ptracers diffusivity

[samar khatiwala]

Hello

Could someone please clarify how PTRACERS_diffKh interacts
with GM/REDI?

Suppose I have:
 PTRACERS_diffKh(1)=0.E3,
 PTRACERS_useGMRedi(1)=.TRUE.

Will the Redi part of GMREDI (isopycnal diffusion) be applied to this
ptracer? If so, what diffusivity will be used (I'm guessing
GM_background_K etc)?

On the other hand, what happens if I have:
 PTRACERS_diffKh(1)=1.E3,
 PTRACERS_useGMRedi(1)=.TRUE.
(and useGMRedi=.TRUE.)
Will horizontal diffusion AND Redi isopycnal diffusion both be
applied?

I cannot figure out what PTRACERS_useGMRedi does.

Thanks very much
Samar