Physics-side sponge layer diffusion coefficients are not being applied
Opened this issue · 2 comments
What happened?
The sponge layer diffusion coefficients for momentum set in src/physics/cam/vertical_diffusion.F90 are not being applied to the sponge layer. This bug impacts mid-top, WACCM and WACCM-X configurations. In the following loop adding kvm_sponge to kvm:
!
! add sponge layer vertical diffusion
!
if (allocated(kvm_sponge)) then
do k=1,size(kvm_sponge(:),1)
kvm(:ncol,1) = kvm(:ncol,1)+kvm_sponge(k)
end do
end if
kvm has a hard coded level index of 1, where it should instead be k.
A separate issue with this code is that the kvm array is on the pverp grid, meaning level 1 is the top of the model, and are therefore of no consequence because the fin_vol_lu_decomp diffusion solver code uses a fixed or zero flux boundary condition. This implies the values of kvm_sponge(1) are also not of any consequence, even after fixing the bug. Running two simulations and varying kvm(:ncol,1), the answers are bfb, confirming that the model top kvm values are not used.
What are the steps to reproduce the bug?
Run FMTHIST or a WACCM/-X compset
What CAM tag were you using?
cam6_4_038
What machine were you running CAM on?
CISL machine (e.g. cheyenne)
What compiler were you using?
Intel
Path to a case directory, if applicable
No response
Will you be addressing this bug yourself?
Yes
Extra info
@PeterHjortLauritzen @adamrher Is this a bug that needs correcting in prior versions of the code, or did it creep in recently?