WACCM DECK runs should be configured similarly to CAM DECK runs, but
without virtual elevation classes over Antarctica. At 2-degree we
+also decided to NOT turn on Carbon isotopes.

(2018-10-22) In discussions between Bill Sacks and Bill Lipscomb: We
have decided NOT to turn on virtual Antarctica columns for any of the
WACCM simulations (DECK or ScenarioMIP): these weren't turned on in the
WACCM PI-Control or historical runs (either by accident or
intentionally: I'm not sure which, and can't find emails describing this
decision). Since this setting needs to be compatible with the REFCASE,
it's simpler if we keep it consistent for all WACCM runs, and there
seems to be only limited value in turning on virtual Antarctica columns
in the remaining WACCM runs (1% CO2, 4xCO2 and ScenarioMIP) when they
weren't on in the WACCM PI-Control or Historical runs. And Mike Mills
says that there won't be any more sharing of initial conditions between
CAM and WACCM CMIP6 runs, so it's fine if the two sets remain different
in this respect.
