Affected Releases - CESM1.0.z, CESM1.1.z and CESM1.2.z
(Bugzilla 2069)
This bug affects WACCM, but not CAM or WACCM-X.
When WACCM-X was merged to the CAM trunk and the CESM 1.0 release series, molecular diffusion ("kvt") was no longer added to kvh, so that WACCM-X and the parameterized gravity waves could treat molecular diffusion separately from eddy diffusion from the PBL scheme.
However, the diffusion solver was not updated to reflect this for WACCM, so the effect of molecular diffusion on heat was accidentally removed from the model.
This bug affects CESM 1.0.4-1.0.6, and all CESM 1.1 and CESM 1.2 releases.
The attached versions of diffusion_solver contain a fix tested on CESM 1.0.6 and CESM 1.2.2, which cause temperature profiles in the mesosphere to more closely reflect the values in earlier runs (e.g. CMIP5 WACCM runs). The appropriate file for your version should be decompressed (i.e. with "gunzip"), renamed to "diffusion_solver.F90", and then placed into either SourceMods/src.cam, or into the CESM source directory at models/atm/cam/src/physics/cam.
(Bugzilla 2069)
This bug affects WACCM, but not CAM or WACCM-X.
When WACCM-X was merged to the CAM trunk and the CESM 1.0 release series, molecular diffusion ("kvt") was no longer added to kvh, so that WACCM-X and the parameterized gravity waves could treat molecular diffusion separately from eddy diffusion from the PBL scheme.
However, the diffusion solver was not updated to reflect this for WACCM, so the effect of molecular diffusion on heat was accidentally removed from the model.
This bug affects CESM 1.0.4-1.0.6, and all CESM 1.1 and CESM 1.2 releases.
The attached versions of diffusion_solver contain a fix tested on CESM 1.0.6 and CESM 1.2.2, which cause temperature profiles in the mesosphere to more closely reflect the values in earlier runs (e.g. CMIP5 WACCM runs). The appropriate file for your version should be decompressed (i.e. with "gunzip"), renamed to "diffusion_solver.F90", and then placed into either SourceMods/src.cam, or into the CESM source directory at models/atm/cam/src/physics/cam.