[CF-metadata] CF and a representation of probalistic forecasts

From: Jonathan Gregory <j.m.gregory>
Date: Mon, 12 Feb 2007 21:28:47 +0000

Dear all

Bryan asked "How is that different from differing methods of cell methods with
the same standard names?" That's a good question: I suppose I'd say that we
would use the same cell_methods entry to indicate a mean, for instance,
regardless of how it had been weighted. At the moment we can only record that
by a non-standardised comment in cell_methods such as "(area-weighted)". But
quantities which could be used for weights in this situation might be in data
variables and could be distinguished by standard names, for instance cell_area
or land_area_fraction. I think the realization weights are more analogous to
those quantities than they are to different cell methods.

I agree with Steve that the realization weights are a bit like masks. I think
CF would distinguish between mask quantities by standard names too, though at
present the only one we have in the table is land_binary_mask.

Jamie remarked, "I think the weights are the same kind of quantity even if they
are calculated different ways - just as air_temperature is considered the
same quantity even if calculated from a GFDL model or a ECMWF model." That
might be the case, I suppose; two sets of weights might simply be alternative
values for the same quantity. If they came from different models that could be
indicated in other ways (as in the ensembles discussion). I'm not sure of what
examples to use - perhaps you could suggest some - but maybe you might have
weights that were based on the realism of historical temperature simulation
for instance, or on a measure of quality of present-day mean climatology. The
quantities being used for assessment could have standard names, and they would
be different names. Hence so should weights based on them, I suggest.

Cheers

Jonathan
Received on Mon Feb 12 2007 - 14:28:47 GMT