[CF-metadata] The use of CF cell constructs for point data

From: Jonathan Gregory <j.m.gregory>
Date: Mon, 9 Apr 2012 20:07:53 +0100

Dear Randy

> The GOES-R system will be producing a hemispheric lightning detection product.
>
> It will be an array of lightning detection that occur within some number of seconds across the western hemisphere (i.e. it is not a gridded product).

Is is a timeseries of values, for probability or number of occurrence or
yes/no - something like that? If so, I don't think there's a featureType for
it yet. It's a timeseries which doesn't apply to a station. It would be
among the list of things not covered by chap 9 yet (see sect 9.1). But you
don't need to give it a featureType. Chap 9 is primarily for datasets which
need to use the techniques provided there for saving space.

> A lightning detection has a center location, and needs to be associated with an area and an interval of time.
>
> (2) Use the cell "bounds" construct to capture the time interval.

Fine. cell_methods should say "time: sum", where time is the name of the time
dimension. From your description, I think "sum" is appropriate because this
quantity is extensive in time. The probability would be larger if the interval
were longer. See App E.

> (3) Use the cell "cell_measures" construct to capture area (i.e. ":cell_measure = area: lightning_detection_area").

That's not quite right, I think. The entry is to indicate what kind of
statistic this is, and I would say that again this is extensive. If you
considered an area smaller than the W hemisphere, the probability would be
smaller, for instance. So I would suggest "area: sum".

Cheers

Jonathan
Received on Mon Apr 09 2012 - 13:07:53 BST