Adjust trop_cloud_top_lev for cam4 runs

[cacraigucar]

What is the feature/what would you like to discuss?

Inside CAM's cloud_fraction.F90, trop_lev is adjusted to = 1 when macrop_scheme="rk". Since this is only set for CAM4 runs, we need to adjust this setting when CAM4 is implemented.

Is there anyone in particular you want to be part of this conversation?

No response

Will this change (regression test) answers?

No

Will you be implementing this enhancement yourself?

No

[jimmielin]

I've split that part of the cldfrc calculation off into a separate scheme, and introduced a CCPP variable vertical_layer_index_of_cloud_physics_top? that individual macrophysics schemes can set at initialization (so this has to be in the registry) to control the trop_lev.

I feel it will be cleaner this way to have this information contained in macrophysics schemes rather than let cloud_fraction query the model configuration like it was done in CAM for portability.

For cloud_fraction_fice I'll have to modify the metadata to do the same changes and assign it to the right value somewhere in initialization.