sum (expr, dim1, dim2, <,tinc> <,-b>)
Sums the result of
expr over the specified dimension range.
If the summing dimension is time, an optional time increment
may be specified.
expr- any valid GrADS expression
dim1- the start point for the sum
dim2- the end point for the sum
tinc- optional increment for time summing
-b- use exact boundaries
dim2 are standard
GrADS dimension expressions whose dimensions must match.
dim2are specified in world coordinates, the coordinates are converted to the nearest integer grid coordinates based on the scaling of the default file.
-bboundary flag is specified. The boundry flag indicates that the sum should be taken to the exact boundaries specified by
dim2, rather than the nearest grid points.
asumfunction recognizes this and weights appropriately. To calculate an sum without any weighting, use the