KMT returned from get_grid does not include overflow pop-downs

[matt-long]

Here is diff between pop_tools.get_grid('gx1v7').KMT - ds_ref.KMT, where ds_ref was read from model output:

KMT is depressed by 1 at the overflow locations.

Not clear how to proceed here...

[mnlevy1981]

Could you add an include_overflow option to get_grid() and then mimic POP when include_overflow = True? I only sort of understand the overflow code, but if the overflow locations are hard-coded in the POP codebase then they'd need to be hard-coded into get_grid() as well; if instead POP sets it up based on a configuration file somewhere, pop-tools would need to access that same file.

Implementation detail, but I would have the default value of include_overflow be None, and then do something like

if include_overflow is None:
    include_overflow = grid_name.startswith('gx1')

(because we only use overflows in the 1 degree grid, right?)

[matt-long]

The overflow parameterization reads an input file that specifies the KMT "pops." We could read that file and do what you suggest.