Fig. 2.2 - The PIRCS 1/2-degree latitude-longitude grid.  Every second grid
point of the inner domain is marked with a +; every second grid point of
the outer domain (forcing frame) is marked with a o.
Orientation of the inner domain:
Central point      (LAT=26, LON= 51) (37.5 N, 100.0 W)
Lower left corner  (LAT= 1, LON=  1) (25.0 N, 125.0 W)
Upper right corner (LAT=51, LON=101) (50.0 N,  75.0 W)