Atmosphere-Ocean Model 4x3 Grid
The Atmosphere-Ocean Model divides the horizontal surface of the
Earth into grid cells of 4° in longitude by 3° in latitude. The 90
grid cells in longitude are numbered from west to east with the first
cell being between the International Date Line and 176°W. There are 60
grid cells in latitude of 3° each numbered from south to north with the
first cell being between the South Pole and 87°S. Most quantities will
have the same value for all cells touching the South Pole. The same
applies to cells touching the North Pole.
The Atmosphere-Ocean Model uses the index I to number grid cells
in longitude and the index J to number grid cells 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 cell (I,J) is between I*4-184 and I*4-180 degrees of longitude and
between J*3-93 and J*3-90 degrees of latitude. A location at X degrees
of longitude and Y degrees of latitude resides in grid cell
[Nint(45.5+X/4),Nint(30.5+Y/3)] when these values are rounded to the
nearest integers.
1 1 1 1 1 1 1 1
8 7 7 6 6 7 7 8
0 6 2 8 8 2 6 0
W W W W E E E E
90N +-------+-------+-------+ . . . . +-------+-------+-------+ 90N
| |
| polar circle |
| |
87N +-------+-------+-------+ . . . . +-------+-------+-------+ 87N
| | | | | | | |
| 1,59 | 2,59 | 3,59 | | 88,59 | 89,59 | 90,59 |
| | | | | | | |
84N +-------+-------+-------+ . . . . +-------+-------+-------+ 84N
| | | | | | | |
| 1,58 | 2,58 | 3,58 | | 88,58 | 89,58 | 90,58 |
| | | | | | | |
81N +-------+-------+-------+ . . . . +-------+-------+-------+ 81N
. . . . . . . .
. . . . . . . .
. . . . . . . .
. . . . . . . .
81S +-------+-------+-------+ . . . . +-------+-------+-------+ 87S
| | | | | | | |
| 1,3 | 2,3 | 3,3 | | 88,3 | 89,3 | 90,3 |
| | | | | | | |
84S +-------+-------+-------+ . . . . +-------+-------+-------+ 84S
| | | | | | | |
| 1,2 | 2,2 | 3,2 | | 88,2 | 89,2 | 90,2 |
| | | | | | | |
87S +-------+-------+-------+ . . . . +-------+-------+-------+ 87S
| |
| polar circle |
| |
90S +-------+-------+-------+ . . . . +-------+-------+-------+ 90S
1 1 1 1 1 1 1 1
8 7 7 6 6 7 7 8
0 6 2 8 8 2 6 0
W W W W E E E E
2009/10/15