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[CF-metadata] Climatological Stats

From: Karl Taylor <taylor13>
Date: Fri, 11 Sep 2015 10:34:38 -0700

Dear Ajay,

Since "month" is not a proper unit of measure, convert your times to
days and use a unit "days since ...".

Also, it is normally a bad idea to have your base time set to a date
before the switch from Julian to Gregorian calendar. I suggest using a
base time of "1955-01-01" (i.e., the beginning of your climatological
period).

I think the cell_methods should be:

cell_methods="area: mean depth: mean time: mean within years time: mean over years";

The time bounds should be (expressed in date/time format):

climatology_bounds = "1955-01-01", "2012-04-01"

and you can choose your time coordinate value as you think most appropriate, e.g.,
the middle of the season of the first year of the climatology, or
the beginning of the first month of the first year of the climatology, or
the middle of the season of the middle year of the climatology, or

???


Hope someone confirms this, as sometimes I make a mistakes.

Karl




On 9/11/15 9:54 AM, Ajay Krishnan - NOAA Affiliate wrote:
> Dear CF members,
>
> I would like your input on the way climatological stats are being
> represented in a file that I am working on. I believe that I am not
> using the time and the climatological_bounds properly:
>
> Seasonal SST
>
> Average seasonal temperature (Jan-Mar) for 6 decades (1955-2012)
>
> dimensions:
> time=1;
> nv=2;
> variables:
>
>
> double time(time);
> time:climatology="climatology_bounds";
> time:units="months since 0000-01-01";
> double climatology_bounds(time,nv);
>
>
> double climatology_bounds(time,nv);
>
> climatology_bounds:comment=? This variable defines the bounds of the
> climatological time period for each time? ;
>
> float t_mn(time,lat,lon,depth);
> t_mn:standard_name: ?sea_water_temperature? ;
>
> t_mn:long_name: ?Average of all unflagged interpolated values at each
> standard depth level for sea_water_temperature in each grid-square
> which contain at least one measurement.? ;
>
> t_mn:cell_methods: ?area: mean depth: mean time: mean? ;
>
>
> data: // time coordinates translated to date/time format
> time= ?1.5? ;
>
> climatology_bounds=?0.0?, ?3.0? ;
>
>
> The CF examples are helpful but my case is different where in I have
> just 1-time co-ordinate in my file. In the above case, what is the
> best way to record time and climatology bounds?
>
>
> Thanks,
>
> Ajay
>
>
>
>
> _______________________________________________
> CF-metadata mailing list
> CF-metadata at cgd.ucar.edu
> http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata

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