Ice and Mud file specification in ww3_multi.inp

[noaa-emc]

Ice and Mud file specification in ww3_multi.inp

[ajhenrique]

Erick Rogers (NRL) indicated ww3_multi uses different approach for new source terms, as follows:

With multi.inp, there are those 'yes 'no' 'yes' 'yes' things and we
didn't want to add 5 to 10 new yes/no's to that list.

So, if you want multi and not shel, there are two approaches.

1. use namelist variables that are set in ww3_grid.inp. This is probably
   where you want to start. Downside: the "variable" is constant in space
   and time. It is only "variable" in the sense that you can change it from
   one simulation to another.
2. use multi.nml. This permits the "variable" to actually change in
   space and time. This work was done by Mickael (cc'd) and you can just
   follow and extend his approach. Of course, you would also need to do the
   work that Mark Orzech and I did, which is to add the new "field"
   variables in various parts of the code needed for both shel and multi.
   In fact, it may be easier to start with the shel functionality, and then
   add in the hooks for multi.nml second. In other words, following the
   sequence used by Mark/me/Michael.