[CF-metadata] Return periods

From: Jonathan Gregory <j.m.gregory>
Date: Fri, 19 Sep 2014 14:57:12 +0100

Dear Ben

Thanks for your comment.

> >> You are right regarding the calculation - we are using a statistical model
> >> of the relationship between monthly rainfall and return period that was
> >> developed many years ago by a colleague from an analysis of 60 years
> >> of historical data.
> [...]
> > Right. So it is reasonable to describe it as a conversion of precipitation
> > amount to probability, I think.
>
> > It would be useful to know if anyone else reading this has a view on my
> > suggestion of precipitation_amount_converted_to_cumulative_probability.
>
> Yes, I have a slightly more general view of this. I think it is not so useful to try to include the whole or part of the data processing that produced the values _as part of the variable name itself_. For many practical applications it is most relevant for its use to know what the data _is_, not where it came from or how in details how it came about.
>
> Thus with this particular case as example I would rather have preferred something more direct like one of these:
>
> precipitation_amount_cumulative_probability
> precipitation_cumulative_probability
> cumulative_precipitation_probability

cumulative_probability_distribution_of_precipitation_amount would be OK in
this case, but I didn't suggest that because Dan isn't really using
it as a CDF, so that could be confusing. However it would be more general
if phrased that way, and so could be preferable.

cumulative_precipitation_probability would be too general, I think. For the
purpose required, it must indicate it is precipitation amount. If it was a
PDF, you could not have a standard name of probability_density_function,
because the units depend on the quantity of which it is a PDF, and therefore
there must be different standard name for PDFs of precipitation_amount and
air_temperature, for example. We have a standard_name guidelines for PDF
names and (non-cumulative) probability distributions, but not for CDF names
(presumably because the need has not arisen before).

Best wishes

Jonathan
Received on Fri Sep 19 2014 - 07:57:12 BST