Add a shift to each ocean boundary node based on latitude as:
linear transition:
lats=[0, 27, 28, 32, 33, 90]  # degrees
msl_shifts=[-0.25, -0.25, 0.0, 0.0, 0.56, 0.56]  # m

1). Install Python library on your system: git clone git@github.com:wzhengui/pylibs.git 

2). Add PYTHONPATH environmental variable to the python libaray
   e.g. on C-Shell: setenv PYTHONPATH 'YourDir/pylibs/Scripts/:YourDir/pylibs/Utility/' 

3). Copy this folder to your run folder and "cd Tweak_elev2D"

4). Link the original elev2D.th.nc to the current folder.

5). run ./modify_elev.py and the output is elev2D.th.modified.nc

6). the script will replace the existing elev2D.th.nc in the run dir (../) with the modified one.
