Re: [ferret_users] return=tstart,p=1

[Ansley Manke <ansley.b.manke@xxxxxxxx>]

Hi David,
One way to deal with this is with the one of the Time axis functions (SHOW FUNCTION TAX*)

yes? show func tax_year
TAX_YEAR(A,B)
    Returns years of time axis coordinate values
    A: time steps to convert
    B: variable with reference time axis

Here, use the coordinate value  from the time axis at L=1 for the time step, and a list of the coordinates as the second argument. The monthly_navy_winds dataset included with Ferret has a non-zero first year, but coads_climatology, being a climatological axis, returns a null for the start

yes? use monthly_navy_winds
yes? list tax_year (`t[gt=uwnd,L=1]`, t[gt=uwnd])
 !-> list tax_year (17598, t[gt=uwnd])
             VARIABLE : TAX_YEAR (17598, T[GT=UWND])
             FILENAME : monthly_navy_winds.cdf
             FILEPATH : /home/porter/tmap/ferret/linux/fer_dsets/data/
          1982

yes? use coads_climatology
yes? list tax_year (`t[gt=sst,L=1]`, t[gt=sst])
 !-> list tax_year (366, t[gt=sst])
             VARIABLE : TAX_YEAR (366, T[GT=SST])
             FILENAME : coads_climatology.cdf
             FILEPATH : /home/porter/tmap/ferret/linux/fer_dsets/data/
          0.0000




David Wang wrote:

Hello Ferreters,

I'm using `var,return=tstart,p=1` to return the starting year and likewise the ending year. However when the starting year is 0, the command returns nothing (a null string) which causes troubles when I'd like to assign the value to other variables/symbols. My intention is to calculate multi-year means and variances from monthly data by the approach described here at http://ferret.pmel.noaa.gov/FERRET_17sep07/FAQ/analysis/annual_from_monthly.html
I need the starting and the ending years of the original time axis to define a new time axis. Any clues?

yes? say `temp,return=tstart`
 !-> MESSAGE/CONTINUE 16-JAN 12:00
16-JAN 12:00

yes? say `temp,return=tstart,p=1`
 !-> MESSAGE/CONTINUE

 

Thanks very much,
David