Dear all,
I am loosely following the CF discussions. But here I stumbled: if
you have a variable changin over time, then its physical unit can't be
"Pa" any longer but should be "Pa s-1" in SI units or something like "Pa
(3h)-1" if the seconds are inconvenient. Looks like one of those
problems where habits have generated their own rules which makes it
difficult to formulate them in precise physically correct rules.
Best regards,
Martin
Message: 2
Date: Fri, 29 Jun 2007 09:42:33 -0700
From: "Godin, Michael" <godin at mbari.org>
Subject: [CF-metadata] Proposed cell_methods method
CF Community,
In another community, a member is trying to correctly represent a
variable with a long name of "3 hour pressure change". The variable has
units of Pa, so I believe it's standard name should be "air_pressure",
not "tendency_of_air_pressure". However, the variable should probably
have a cell_methods attribute that indicates this is a change over time,
not an absolute measurement. But how to do so?
Perhaps something like cell_methods="time: change (interval: 3 hour)"
But there is no cell_method in appendix E like "change".
The alternative is to propose a new standard name
"change_over_time_in_air_pressure", but doing so seems inelegant.
Mike
_____________________________________________
Michael A. Godin
Software Engineer
Monterey Bay Aquarium Research Institute
Phone: 831-775-2063
http://www.mbari.org
Forschungszentrum Juelich GmbH
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Sitz der Gesellschaft: Juelich
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Vorsitzender)
Received on Wed Jul 11 2007 - 07:46:20 BST
