[ferret_users] composite of active phase

[jaya kumar A <jayamet@xxxxxxxxx>]

dear ferret users,
I want to calculate the composite of active phase which corresponds to different dates in the JJAS ,
if i pick the dates from the different years I tried like this 
let SD_posv=SAMPLEL(PRE_ANOM_NEW[d=1],{171, 204, 195, 2002, 12.....})
con/lev=(0.2,2,0.2)/nolab/nokey SD_posv[l=@ave]

will this method is ok?
if it is wrong any good method to make
I also want to make a time series of 20 days before and after active phase so  if i define SD_posv as active phase (above)

with regards
jaya

-- 
JAYAKUMAR A
Senior Research Fellow, 
Theoretical Studies Division
IITM, Pune-8