# saving seasonal values (djf, mam, jja, son) on to a continuous time axis

Ferret also can make DJF time series!! (ref, ref2, ref3)

use sst.nc
let month=l[gt=temp]
let DJF = if (mod(month,12) le 2) OR (mod(month,12) le 2) then 1
let MAM = if (mod(month,12) ge 3) AND (mod(month,12) le 5) then 1
let JJA = if (mod(month,12) ge 6) AND (mod(month,12) le 8) then 1
let SON = if (mod(month,12) ge 9) AND (mod(month,12) le 11) then 1
let winter_sst=temp*DJF
let spring_sst=temp*MAM
let summer_sst=temp*JJA
let fall_sst  =temp*SON

let sst_compr_djf = COMPRESSL(winter_sst)
list/x=60/y=15/l=1:10  sst_compr_djf
PAUSE

! 1870-2010 –> 140 years –> 140*3=420 data points (time axis)
!defining to abstract axes one to put the data on the time axis
define axis/t=1:420:1 t420
let sst_djf = winter_compr_djf[gt=t420@ASN]
list/x=60/y=15/t=1:10 sst_djf   !(or we can save the data or plot)

! Similarly we can extract MAM, JJA, SON.  Please take care in case of DJF values extraction and check before you use the extracted data.

Bonus!!

<seaonal mean> ref

let djf = d_j_f[l=@sbx:3]

save/file=djf.nc djf[l=1:90:3]

So, Simple. 🙂 even powerful.