Enable new exchange of CAM computes enthalpy which is sent to BLOM

[mvertens]

Description of changes

Enable new exchange of CAM computes enthalpy which is sent to BLOM

Specific notes

This PR supersedes #36

CAM now sends to BLOM a new enthalpy flux as required for energy consistency with atmospheric water exchange.
This is based on an implementation of Thomas Toniazzo.

• This is triggered by the new nuopc.runconfig variable atm_computes_enthalpy_flux. By default this is false. Adding a user_nl_cpl setting of .true. ensures CAM will export/ and BLOM will receive the required fields.

• Due to restrictions in BLOM, what is sent are two fields - the heat flux components due to material material enthalpy flux of the enthalpy flux of evaporation (Faxa_hmat) and the ocean average of all other enthalpy flux components (Faxa_hmoa). In addition, the enthalpy associated with river is sent back to the atm.

• A new budget table version (v2) has been added to account for these new fluxes.

• The following PRs are needed to have the exchange enabled

  • Changes needed for CAM computing enthalpy -> mediator -> BLOM BLOM#675
  • CAM computes enthalpy to send to BLOM CAM#240
    • CAM computes enthalpy to send to BLOM OSLO_AERO#62
    • CAM computes enthalpy to send to BLOM atmospheric_physics#2

Contributors other than yourself, if any: @matsbn Thomas Toniazzo.

CMEPS Issues Fixed: None

Are changes expected to change answers? bfb if enthalpy exchange is not enabled

Any User Interface Changes (namelist or namelist defaults changes)?

• new namelist variables atm_computes_enthalpy_flux and med_computes_enthalpy_flux . By default both are false - and med_computes_enthalpy_flux is used only by CESM not by NorESM.

Testing performed

• ran prealpha_noresm with noresm3_0_beta03a and above PR changes and results were bfb with noresm3_0_beta03a.