Re: [ferret_users] climatological standard deviation

[DELCLAUX Francois <delclaux@xxxxxxxxxxxxxxxxxxx>]

Well, many thanks, it works fine.

Regards

François

> Le 23 sept. 08 à 08:45, DELCLAUX Francois a écrit :
>
> > Hi Ferret users,
> >
> > I have a montly time series over a several year period.
> > It's easy to compute a monthly climatology (12 values) using the time 
> > axis  "month_reg"
> > from the file "climatological_axes"
> >
> > Now, I would like to calculate the corresponding standard deviation, 
> > ie the 12 values
> > calculated from the january values, february values, etc.
> > What's the best way for such a calculation ?
> >
> > Regards
>
> François,
>
> You may use the @MODVAR operator. Something like that :
>
> DEFINE 
> AXIS/T="01-JAN-1840":"31-DEC-1840"/NPOINTS=12/CALENDAR=360_DAY/MODULO/EDGES/UNIT="Year"     
> mois_clim
> DEFINE 
> AXIS/T="01-JAN-1840":"31-DEC-2409"/NPOINTS=6840/CALENDAR=360_DAY/MODULO/EDGES/UNIT="Year"   
> mois
>
> LET/TITLE="Sea surface temperature"/UNITS="C" sst = sosstsst[GT=mois@ASN]
> LET/TITLE="Sea surface temperature, Mean seasonal cycle"/UNITS="C" 
> sst_se = sst[GT=mois_clim@MOD]
> LET/TITLE="Sea surface temperature, anomaly"/UNITS="C" sst_ano = sst - 
> sst_se
> LET/TITLE="SST, interannual variance"/UNITS="C" sst_var = 
> sst[GT=mois_clim@MODVAR]^0.5
>
> Regards,
>
> Olivier