This function returns the X location of minimum grid value over a spatial domain. The syntax is:
 aminlocx(expr, xdim1, xdim2, ydim1, ydim2)
where:
expr    any valid GrADS grid expression xdim1   starting X or LON dimension expression xdim2   ending X or LON dimension expression ydim1   starting Y or LAT dimension expression ydim2   ending Y or LAT dimension expression For the X location of the global minimum, a shorthand may be used:
aminlocx(expr, global) or aminlocx(expr, g)
aminlocx(expr, lon=0, lon=360, lat=-90, lat=90)
minloc and min functions. 
aminlocy will return the Y  location of the minimum grid value. 
amin function to retrieve the minimum value over the grid.  
amax, amaxlocx, and amaxlocy.
amin.