Re: [ferret_users] error in producing seasonal mask JJAS

[Peter Szabo <szabpet83@xxxxxxxxx>]

Dear Archana,
i would write something like this for your task:

let month = l[gt=rt]
let jjas = if (mod(month,12) le 9) and (mod(month,12) ge 6) then 1 else 0 
!function mod gives the residuum, it is really good for masking in time. 
!if rt can be 0- like temperature in Celsius- or you want an average then leave "else 0" at the end of the masking
let rt_jjas = rt * jjas !your data set should look like something like this:
0,0,0,0,0,xj,xj,xa,xs,0,0,0 (or missing data instead of the 0s)
let ave_rt=rt_jjas[t=@ave] !this gives you JJAS-seasonal time-series average

after this you can have computations (like x=80:92@ave,y=26:30@ave and so on).

Peter Szabo