Hello Jonathan,
I don't see the different pH scales as the same geophysical quantity measured in different ways. I see them more as subtley different geophysical quantities (activities or concentrations of different groups of species) expressed through a common syntax (negative log transform).
My initial reaction to an additional attribute is one of caution. I can see the need but have concerns as to how it would be populated. Plaintext doesn't scale and standardised sensor descriptions have kept a group of us in MMI pretty busy over the past year, which makes doing the same for analytical methods look very daunting.
Cheers, Roy.
-----Original Message-----
From: cf-metadata-bounces at cgd.ucar.edu [mailto:cf-metadata-bounces at cgd.ucar.edu] On Behalf Of Jonathan Gregory
Sent: 08 May 2009 10:29
To: cf-metadata at cgd.ucar.edu; Lowry, Roy K
Subject: [CF-metadata] new standard name request for pH
Dear John
Thanks for the helpful information and all your time, and your colleagues',
spent on this.
If the conclusion is "There are several ways of measuring pH and this is the
best one for the circumstances", as you say, it sounds to me that pH is the
geophysical quantity, and "total scale" is a measurement technique. That
means I tend to the solution of not including it in the standard name, and
deciding on another attribute to record it in. We do not define distinct
standard names for different ways of measuring the same quantity. That's a
point that came up, for instance, regarding cloud area fraction from different
satellites. But it is still important to record the information, since the
results may be systematically different. Maybe we need a new CF attribute
for this kind of purpose. What do you think, Roy, Nan and others?
Best wishes
Jonathan
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Received on Fri May 08 2009 - 04:01:17 BST
