(1) The BOXMIX version of the Miami isopycnic coordinate model contains a 
Kraus-Turner mixed layer and is set in a box bounded by latitude/longitude 
lines. The model is documented in: Bleck, Hanson, Hu, Kraus, "Mixed 
layer/thermocline interaction in a three-dimensional isopycnic coordinate 
model", JPO 1989, pp 1417-1439.

(2) Horizontal array dimensions are uniformly set to (IDM,JDM), even though 
many fields do not make use of the full allotted space due to horizontal
staggering considerations. Specifially, there are only (IDM-1)x(JDM-1) mass 
points but IDMxJDM U,V points, including boundary velocity points which are 
set to zero (no-slip sidewalls). U,V points addressed as (I,J) are 
physically located at grid location (I-1/2,J-1/2) relative to mass point 
(I,J) (Arakawa B grid). Vorticity, barotropic mass flux streamfunction, and 
Coriolis parameter are carried at velocity points.

(3) The 2 time slots required for all prognostic and some diagnostic 
variables are incorporated into the third (vertical) array dimension. The 
vertical grid index KM [as in TEMP(I,J,KM)] means model level K, time level 
M (as in "mid" time). Letter N [as in TEMP(I,J,KN)] indicates the "new" and 
"old" time level.

(4) Grid boxes are squares on a Mercator projection, i.e., the mesh size 
on the sphere varies like cos(latitude). For the purpose of defining 
geographic parameters and forcing fields, the x,y axes, together with their 
associated grid indices I,J, are assumed to increase southward/eastward 
respectively. In other words, if the grid is viewed with North pointing 
up, grid points are numbered like matrix elements. 

(5) Bottom depth is allowed to vary in west-east (J) direction.

(6) The model uses a rigid lid and requires a Fast Fourier Transform routine 
for diagnosing the barotropic stream function at each time step.

(7) BOXMIXPROC is a model processor which produces contour plots of 
velocity, temperature, layer thickness, layer streamfunction, ventilation 
tracer, etc., in horizontal and vertical planes.

(8) To eliminate the line numbers appended to the beginning of each line 
in the source code BOXMIX.SOURCE, enter the UNIX editor vi and issue the 
command :1,$s/.....//  (the line numbers are useful for communication 
between users and author).

                                                            Rainer Bleck