[ferret_users] defining a var consisting of two vars on different time axes

[Peter Szabo <szabpet83@xxxxxxxxx>]

Hi Ferreters,

I came across an odd behaviour of Ferret (at least it is strange for me). I have two daily data sets, one concerns 1961-1990, while the other one is for 2021-2050.

I try to have yearly anomalies from an average of the past.

1) I define a time axis which counts yearly sums for the future.

let start = 2020

let run = l[l=1:31]

let year = start + run

def ax/un=days/t0=1-jan-1900/ed year2150=days1900(year,1,1)

2) If I try to plot these anomalies in two different ways, I get different results, more precisely, the first method is not working, while the second one is just perfect. Though, it seems that final variables are defined the same way. Why is that?

yes? let r1=pre61r[l=1:10957@sum]/30

yes? let r2=pre21r[gt=year2150@sum]

yes? let r2150=r2-r1

yes? plot r2150

 **ERROR: illegal limits: SDIIR1 is not in the range T=01-JAN-2082 00:00:02-JAN-2112 00:00

          Axis extremes are T=01-JAN-1961 00:00:01-JAN-1991 00:00

yes? let r2150=pre21r[gt=year2150@sum]-pre61r[l=1:10957@sum]/30

yes? plot r2150

Regards,

Peter