Dear Jonathan,

Indeed, this looks like good solution. And to follow this line of thoughts to 
its end; by shifting the order of the operations to
      time: mean within years (period: 1 month) time: range time: mean over 
years
it should be possible to have one file containing a series of successive 30 
year (say) averages of annual spans between monthly mean temperatures
 
I note that ticket 82 has gone dormant since almost a year, there was not much 
discussion and the comments were largely positive. Any chance that it will be 
resurrected?


Many thank you for you constructive input.

Lars


-----Original Message-----
From: CF-metadata [mailto:cf-metadata-boun...@cgd.ucar.edu] On Behalf Of 
Jonathan Gregory
Sent: den 13 maj 2016 17:23
To: cf-metadata@cgd.ucar.edu
Subject: Re: [CF-metadata] climatological statistics --- climate indices

Dear Lars

When you compute the third operation (the range over climatological months) you 
collapse the time axis to size 1, so it no longer indicates that it was months. 
It might previously have been days, 5-day periods, or anything else.
I think this case could be dealt with by the proposed (but not agreed) con- 
vention for multiple processing of axes in cf-trac.llnl.gov/trac/ticket/82.
Something like

time: mean within years (period: 1 month) time: mean over years time: range

might work.

Best wishes

Jonathan

----- Forwarded message from Bärring Lars <lars.barr...@smhi.se> -----

> Date: Fri, 13 May 2016 14:09:25 +0000
> From: Bärring Lars <lars.barr...@smhi.se>
> To: Jonathan Gregory <j.m.greg...@reading.ac.uk>, "cf-metadata@cgd.ucar.edu"
>       <cf-metadata@cgd.ucar.edu>
> Subject: RE: [CF-metadata] climatological statistics --- climate 
> indices
> 
> Dear Jonathan,
> 
> > > But how about common continentality indices based on the annual range of 
> > > monthly mean temperatures? 
> > > Is there a "within months" such that the cell method for the basic 
> > > element of the continentality index would be "time: mean within months 
> > > time: range within years" ? Or is there another solution?
> 
> > Climatological stats can be described for the annual cycle. The 
> > climatological monthly mean temperature would be "time: mean within 
> > years
> > time: mean over years", and you would use the climatological time bounds to 
> > indicate the start and end of months (or other portions of the annual 
> > cycle).
> > This would produce twelve climatological monthly values (for each location).
> > Do you mean you then apply a third operation to compute the range of these 
> > twelve values?
> 
> Yes, exactly. 
> 
> And, just to complete the picture, possibly even a to apply fourth operation 
> to calculate a climatological average over e.g. 30 years. In practice, this 
> is of course much simplified if one uses monthly mean temperature data as 
> input because the operations that is actually performed  would be described 
> by the cell method "time: range within years time: mean over years". But this 
> would be an incomplete description of the data.
> 
> Kind regards,
> 
> Lars
> 
> 
> 

----- End forwarded message -----
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