[ferret_users] seasonal climatologies

[Izidine Pinto <izidinep@xxxxxxxxx>]

Dear ferret users

I am comparing two seasonal means of two files 
       file 1 contains daily data from 1jan1981 to 31dec1999
and file 2 contains daily data  only for 'all' DJF for the same period 

 1> ./daily.ppt.1981.1999.era40.nc
name     title                                                     I         J         K         L
 PRECIP   TOTAL PRECIPITATION RATE    1:127     1:110     1:1       1:6939
 
2> ./ppt.DJF.daily.1981_1999.era40.nc  (default)
 name     title                                                         I         J         K         L
 PRECIP   TOTAL PRECIPITATION RATE         1:127     1:110     1:1       1:1683

let pre_monthlycl = precip[d=1,gt=month_reg@mod]     ! 12-month climatology
let pre_3monthav = pre_monthlycl[l=@sbx:3]               ! running 3-month average
save/file=pre_seasonal_alt.nc pre_3monthav[l=1:10:3]  ! save only DJF,MAM,JJA,SON

shade pre_3monthav[l=1]                 ! DJF average
shade PRECIP[d=2,l=1:1683@ave]  ! DJF average

I was expecting to have the same result 
Hope someone can help me to understand why the results differs

Thanks in advance
-- 
I.P.
"In these matters the only certainty is that nothing is certain".  Pliny the Elder (23 AD - 79 AD)