[CF-metadata] new standard names request
Lowry, Roy K.
rkl at bodc.ac.uk
Tue Feb 28 02:40:42 MST 2017
I think there is a CF precedent would pacify you a little here, which is to have Standard Names of the form 'volume_mixing_ratio' with canonical units of dimensionless such as volume_mixing_ratio_of_oxygen_at_stp_in_sea_water. I would suggest following this practice in this case with:
A note to Allen is that your actual units including scaling factor are explicity included in CF NetCDF as a parameter attribute.
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From: CF-metadata <cf-metadata-bounces at cgd.ucar.edu> on behalf of Steve Emmerson <emmerson at ucar.edu>
Sent: 27 February 2017 22:04
To: Allen Jordan - NOAA Affiliate
Cc: CF Metadata Mail List
Subject: Re: [CF-metadata] new standard names request
This is the kind of stuff that I don't like: putting additional (and unnecessary) semantics into the unit specification. "ppm" is bad enough (1e-6 would be better) but *volume*!
The attributes of a physical quantity are attributes of the quantity itself -- *not* its unit. If a physical quantity is atmospheric mixing ratio by volume, then name it as such and leave the unit alone. The alternative is to pollute the unit namespace with "volume", "mass", "carbon", and whatever else people think up -- leading to a unending additions to the units database.
Call the quantity "atmospheric water vapor mixing ratio by volume" and specify the unit as "1e-6" (or "ppm" if you must).
Lest you think I'm alone in this, see sections 7.4 and 7.5 of <https://www.nist.gov/pml/nist-guide-si-chapter-7-rules-and-style-conventions-expressing-values-quantities>.
NIST Guide to the SI, Chapter 7: Rules and Style ...<https://www.nist.gov/pml/nist-guide-si-chapter-7-rules-and-style-conventions-expressing-values-quantities>
7.1 Value and numerical value of a quantity The value of a quantity is its magnitude expressed as the product of a number and a unit, and the number multiplying the ...
Thanks for letting me get this off my chest. :-)
On Mon, Feb 27, 2017 at 2:21 PM, Allen Jordan - NOAA Affiliate <allen.jordan at noaa.gov<mailto:allen.jordan at noaa.gov>> wrote:
I would like to add two standard names for the NOAA GMD OZWV group's weather balloon data:
description: The atmospheric water vapor mixing ratio in parts per million by volume.
description: The atmospheric ozone mixing ratio in parts per billion by volume.
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