[CF-metadata] climatological statistics --- climate indices

From: Jonathan Gregory <j.m.gregory>
Date: Fri, 13 May 2016 16:22:37 +0100

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 B?rring Lars <Lars.Barring at smhi.se> -----

> Date: Fri, 13 May 2016 14:09:25 +0000
> From: B?rring Lars <Lars.Barring at smhi.se>
> To: Jonathan Gregory <j.m.gregory at reading.ac.uk>, "cf-metadata at cgd.ucar.edu"
> <cf-metadata at 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 -----
Received on Fri May 13 2016 - 09:22:37 BST