New Mesh: RRSwISC6to18E3r7

[xylar]

Long name: RRSwISC6to18L80E3SMv3r7

This RRS (Rossby-radius scaled) mesh has:

• 6 km resolution near the poles
• 18 km resolution at the equator

Mesh, initial condition, dynamic adjustment and files for E3SM will be on Chrysalis at:

/lcrc/group/e3sm/ac.xylar/compass_1.3/chrysalis/e3smv3-meshes/rrswisc6to18e3r7

This mesh is similar to RRSwISC6to18E3r5 #801 but with a minimum fraction for partial bottom cells of 0.2 instead of 0.1.

Checklist

• [ ] Document (in a comment titled Testing in this PR) any testing that was used to verify the changes

[xylar]

It seems unlikely we will use this mesh so closing for now.