-------
Purpose
-------
This demonstration case can serve to different purposes:

1) The main one: study of the advection of a patch of ice in a bi-periodic channel with a slab ocean (i.e. 1 ocean layer)
              ==> set ln_icethd=false in namelist_ice_cfg

2) Secondary: study of ice thermodynamics in the same basin
              ==> set ln_icedyn=false in namelist_ice_cfg
              ==> eventually change usrdef_sbc.F90 in MY_SRC to fit your needs

-----------
Experiments
-----------
Two experiments can be configured:

a) A simple channel at 3km horizontal resolution (slightly variable => +- 10%)
              ==> remove key_agrif in cpp keys

b) Same as a) but with an Agrif zoom in the center 1:3, and 3 ghost cells
              ==> add key_agrif in cpp keys

----------
How to run
----------

a) Compile and run the model once to get a mesh_mask.nc file with the following command:
../../../makenemo -a TEST_CASES -n ICEDYN -m X64_ADA -j 4
poe ./opa -procs 1

b) Create the initial condition file for sea-ice (initice.nc) by running this python script: 
python ./make_INITICE.py

c) Run the model a second time
poe ./opa -procs 4

---------------
What to look at
---------------
In case of purpose 1, One can test
---
a) the advection scheme: Ultimate-Macho (ln_adv_UMx=T) versus Prather (ln_adv_Pra=T)
   for a square (ice concentration) or a gaussian (ice volume)
      with either a constant velocity (ln_dynADV=T)
               or a constant ice-atm. stress, thus velocity is calculated by rheology (ln_dynRHGADV=T)
      with 1 or 5 ice categories (jpl=1 or 5)

b) the advection through an agrif zoom 1:3

In case of purpose 2, one can test conservation of properties:
---
c) ice should not change at all if surface fluxes = 0 and SST = freezing temperature

--------------------------------------
Interpretation of the results (remarks)
--------------------------------------
- Prather conserves the max values but also creates side lobes
- UM does not conserve the max but does not create side lobes
- The "unmoving" ice (if any) is due to ice rheology which states that ice mass below a certain thresold (1kg/m2) is considered to move at the ocean velocity (thus 0 m/s)