Merge pull request #691 from alexolinhager/interpolate_ecco_to_mali

Interpolate ECCO ASTE reanalysis to MALI grid

This PR introduces landice/mesh_tools_li/interpolate_ecco_to_mali.py, a script that interpolates ECCO ASTE R1 reanalysis data (https://arcticdata.io/data/10.18739/A2CV4BS5K/) onto a MALI mesh. Relevant ECCO files are stored at: /global/cfs/cdirs/fanssie/standard_datasets/ECCO_Arctic_Subpolar_gyre_sTate_Estimate on Perlmutter.

Ocean temperature and salinity are automatically interpolated and the user has the option to also interpolate sea ice fraction. Interpolation script will generate MALI input field icebergFjordMask from sea ice area if using this option.

ECCO grid files are unconventional for MITgcm simulations and do not contain adequate grid cell corner information for tile edge cells (necessary for creating scrip file and remapping). Therefore, this information needed to be hardcoded into interpolate_ecco_to_mali.py, using grid corner information from adjacent MITgcm tiles. Currently supported tiles are 14 and 27, which cover the western and northern coasts of Greenland.

Author: matthewhoffman