free grads

acos(expr)

abs

abs(expr)

Takes the absolute value of the result of expr. Operates on both gridded and station data. Missing data values do not participate.  

This function takes an areal average over an X-Y region. The syntax is:

aave(expr, xdim1, xdim2, ydim1, ydim2)

where:

expr    - any valid grads expression 
xdim1   - starting X dimension expression 
xdim2   - ending X dimension expression 
ydim1   - starting Y dimension expression 
ydim2   - ending Y dimension expression