Enable MALI Greenland mesh overlap with ocean mesh, through a buffer defined by a geojson file

[andrewdnolan]

This pull request adds a geojson file for 45 km buffer off of the coast of Greenland. This is then used by the Greenland mesh generation testcase.

No major code changes, just adding an input file.

[matthewhoffman]

@trhille , will this line make this new geojson buffer the new behavior? Is that what we want?

[trhille]

Yes, that will make it cull to the geojson file if you set cull_distance < 0 in the .cfg file. If cull_distance > 0, it will cull both to the geojson file and to the uniform distance from the ice margin.
We could set geojson_file in the .cfg file instead of hard-coding it here, for some extra control.

[trhille]

To answer your second question, I think we want this to be the new default behavior, but that could still be introduced through the default .cfg file instead of hardcoded in the script.

[andrewdnolan]

A config option seem like the right call. We can have it on by default if, but also the option turn it off and/or use a different buffer geojson file.

[trhille]

Testing

I successfully created a 4–40km mesh with these changes:

However, I notice that the geojson file seems to extend beyond our bed topography data set in a few places and we get artifacts with bedTopography = 0 at the edge of the mesh:

I'm not sure what's the best way of dealing with this. We could manually edit the geojson to stay within the bounds of the gridded dataset. Or we could set a mask that is the intersection of the two. It's unlikely to ever actually interact with ice, but it's definitely not a desirable feature.