GRID.TXT                                               1999/11/12

     The Atmosphere-Ocean Model divides the horizontal surface of
the Earth into grid boxes of 5 degrees in longitude by 4 degrees
in latitude.  The 72 grid boxes in longitude are numbered from
west to east with the first box being between the International
Date Line and 175 W.  There are 46 grid boxes in latitude because
the triangular grid boxes touching each pole use only 2 degrees
in latitude.  Grid boxes are numbered from south to north in
latitude with the first box being between the South Pole and 88 S.

     The Atmosphere-Ocean Model uses the index I to number grid
boxes in longitude and the index J to number grid boxes in
latitude.  The Model calls west longitude as negative longitude,
calls east longitude as positive longitude, calls south latitude
as negative latitude, and calls north latitude as positive
latitude.  Using these conventions, grid box (I,J) is between
I*5-185 and I*5-180 degrees of longitude and between J*4-96 and
J*4-92 degrees of latitude.


    1       1       1       1           1       1       1       1
    8       7       7       6           6       7       7       8
    0       5       0       5           5       0       5       0
    W       W       W       W           E       E       E       E
90N +-------+-------+-------+  . . . .  +-------+-------+-------+ 90N
    |  polar circle                                             |
88N +-------+-------+-------+  . . . .  +-------+-------+-------+ 88N
    |       |       |       |           |       |       |       |
    |  1,45 |  2,45 |  3,45 |           | 70,45 | 71,45 | 72,45 |
    |       |       |       |           |       |       |       |
84N +-------+-------+-------+  . . . .  +-------+-------+-------+ 84N
    |       |       |       |           |       |       |       |
    |  1,44 |  2,44 |  3,44 |           | 70,44 | 71,44 | 72,44 |
    |       |       |       |           |       |       |       |
80N +-------+-------+-------+  . . . .  +-------+-------+-------+ 80N
    .       .       .       .           .       .       .       .
    .       .       .       .           .       .       .       .
    .       .       .       .           .       .       .       .
    .       .       .       .           .       .       .       .
80S +-------+-------+-------+  . . . .  +-------+-------+-------+ 80S
    |       |       |       |           |       |       |       |
    |  1,3  |  2,3  |  3,3  |           | 70,3  | 71,3  | 72,3  |
    |       |       |       |           |       |       |       |
84S +-------+-------+-------+  . . . .  +-------+-------+-------+ 84S
    |       |       |       |           |       |       |       |
    |  1,2  |  2,2  |  3,2  |           | 70,2  | 71,2  | 72,2  |
    |       |       |       |           |       |       |       |
88S +-------+-------+-------+  . . . .  +-------+-------+-------+ 88S
    |  polar circle                                             |
90S +-------+-------+-------+  . . . .  +-------+-------+-------+ 90S
    1       1       1       1           1       1       1       1
    8       7       7       6           6       7       7       8
    0       5       0       5           5       0       5       0
    W       W       W       W           E       E       E       E