Cherrypick PR283 from dev/emc to main

[laurenchilutti]

Description

When cherry-picking the changes from PR #283 I noticed that model/fv_regional_bc.F90 should also be modified to have an axis type matching the precision that the dycore is built with and not hard-coded double precision.

Fixes # (issue)

How Has This Been Tested?

Tested with SHiELD on Gaea

Checklist:

Please check all whether they apply or not

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• Any dependent changes have been merged and published in downstream modules

[lharris4]

Looks fine, thank you for taking care of this. I see that the calls to register_field in atmos_cubed_sphere all use "double". Should we change that too?

[laurenchilutti]

Yes I think that we should also change the other register_field calls. I will make the changes and do some more testing.