Hello Randye,
G'day
To your query, it is the way that I use to do.
! generate the mask of the variable (var) in the data set, to your query I hope it is the time series you are talking about e.g. ENSO index time series !
let var1 = if var ge 1 then var !! this is the value which is greater than or equal to 1
let var2 = if var le -1 then var !!
this is the value which is less than or equal to -1
list var1, var2 !! this will show you the magnitude with dates !!
save/file=
mask-var.nc var1, var2 !! in case if you want to save them !!
exit
hope this helps, let us know if it doesn't suit your requirement.
Cheers, Saurabh