[CF-metadata] statistic indices

From: Jonathan Gregory <j.m.gregory>
Date: Tue, 17 Jun 2008 18:04:35 +0100

Dear Heinke

> > If a standard_name has the phrase "dependent_on_X" (or whatever phrase is
> > used) it would mean that it must have a coordinate variable, scalar coordinate
> > variable or auxiliary coordinate variable with standard_name of X, to specify
> > the condition.
> >
>
> This gives me a new idea:
>
> /* number of days with daily minimum below 0 degC = frost_days = fd
> (IPCC AR4 and AR5) */
> float n1(lat,lon);
> n1:standard_name="number_of_days_with_variable_below_threshold";
> n1:coordinates="threshold time";
> n1:cell_methods="time: sum over days";
> float threshold;
> threshold:standard_name="air_temperature";
> threshold:units="degC";
> threshold:cell_methods="time:minimun within days"
> data:
> threshold=0.;
>
> The threshold with the term "below_threshold" describes the indicator
> condition.
> The term "number_of_days_with" describes the sum over the indicator value.
> What do you think ? Could we use the scalar coordinate this way ?

Yes, I think this would be OK, except that I would prefer (as in my last email)
that we indicate the "variable" explicitly i.e.
> n1:standard_name="number_of_days_with_air_temperature_below_threshold";
I realise that air_temperature is also a coordinate variable, but I feel that
it we should include it in the standard name as well. For a probability
distribution or a pdf, we would name it in the standard name e.g.
probability_density_function_of_air_temperature. It would be essential to
include it for a pdf, in fact, because the units depend on it (K-1).

Best wishes

Jonathan
Received on Tue Jun 17 2008 - 11:04:35 BST