COARE latent heat bugfix

[mvertens]

Description of changes

This is a fix to NorESM CMEPS that was raised in ESCOMP#684.

Note: the cesm/flux_atmocn/flux_atmocn_Diurnal_mod.F90 also had to be modified to take into account the new subroutine call to cor30a. However, the latent heat computation in flux_atmocn_Diurnal_mod.F90 was not changed. This is a module that has not been in use for a long time - and is there as a placeholder for possible future development. So it's not critical that the latent heat computation for COARE is modified there.

Specific notes

Contributors other than yourself, if any:

CMEPS Issues Fixed: ESCOMP#684.

Are changes expected to change answers? this will change answers more substantially for NorESM which uses the COARE scheme by default

Any User Interface Changes (namelist or namelist defaults changes)? No

Testing performed

A test simulation will be done to determine the impact of this bugfix.

[JensBDebernard]

The changes are in accordance with what we discussed, and looks find. However, I think more investigations should be done before we can include this in the model.

I have done a 20-year run (NorESMhub/noresm3_dev_simulations#484), based on noresm3_0_beta21, but where cmeps is replaced with the head of this branch. The run is identical with NorESMhub/noresm3_dev_simulations#480, expect for the change of cmeps.

Noresm-diagnostics and ADF-diagnostics are found in the issue.
These show surface warming, deep ocean warming, but ADF shows a negative RESTOM. If this is correct, is seems inconsistent with the increased (relative to i480) ocean temperature.

Can someone with more expertise on CAM check that the diagnostics looks correct? (@gold2718 ?)

If the diagnostics are OK, I think we need review from someone with control on the overall assumptions on heat and mass exchange in CAM, and between the models.

If the use of an constant heat of fusion is an underlying assumption in the coupled model, we are violating that with this change. In that case, the use of a non-constant heat of fusion in the coare scheme is also questionable?