[CF-metadata] weighted time mean vs. conditional time mean.

From: martin.juckes at stfc.ac.uk <martin.juckes>
Date: Fri, 20 May 2016 11:09:21 +0000

Hello Jonathan, Jim,

Just picking up the thread again.

There is an issue, it appears, about the use of the "where" modifier for cell_methods elements other than "area:". Jonathan believes "where" should only apply for area on the basis that this where the motivation comes from in the first paragraph of section 7.3.3. The subsequent paragraphs in section 7.3.3. describe the use of "where" with a generic element "name: ....". The compliance document clearly states that "where" can be used with any string.

The specific use case is to specify how the mean should be taken when there is a temporarily varying area_type. Jonathan has suggesed using a suitably formulated free-text comment in brackets ("time: mean (when cloud present)") but I would prefer a formulation with an explicit conventional meaning: "time: mean where cloud".

So there are two questions:
(1) Can "where" be used, as stated by the convention, with any coordinate?
(2) If there is a clear consensus that "where ...." can only be used for "area", then can we update the convention, conformance requirements and CF checker to be consistent with this?

regards,
Martin
Received on Fri May 20 2016 - 05:09:21 BST