"Mass fraction" is a well-defined term and, yes, "ppb" isn't in the sense
that it doesn't specify what a "part" is.
For names of these types of quantities, I highly recommend section 8.6.2 of
<
http://www.nist.gov/pml/pubs/sp811/sec08.cfm>.
Regards,
Steve Emmerson
On Thu, Jun 30, 2016 at 11:56 AM, Lowry, Roy K. <rkl at bodc.ac.uk> wrote:
> Dear All,
>
>
> Having read through the SeaOWL specification provided by Mike's link, I
> see it is something totally new making a combination of fluorescence and
> backscatter measurements at different wavelengths and using the results
> in a calibration algorithm to produce measurements of an analyte that
> WETLabs/SeaBird describe as 'crude oil'. This is NOT the same thing as TPH
> (a wet chemical measurement), although in most environments the two will
> be linearly correlated. I therefore now think that it would be best to
> use the terminology of the instrument manufacturer: i.e. 'crude_oil'.
>
>
> The mass fraction/mass concentration issue is an interesting one. This
> difference has received much attention in the oceanographic research
> community with very precise conversions between mass concentrations to mass
> fractions depending upon variations in temperature, pressure and salinity.
> However, I strongly suspect that the 'ppb' units of the new instrument have
> an assumption of pure water density somewhere in the calibration algorithm
> and take no account of salt water density variations. In other words 'ppb'
> means BOTH unit mass per unit mass and unit mass per unit volume.
>
>
> Having given this some thought, I think Mike's original mass fraction is
> probably the better choice as without further information we can only
> assume that 'ppb' is dimensionless. So, this gives us:
>
>
> mass_fraction_of_crude_oil_in_sea_water
>
>
> Is this agreeable to all? If so, all we need is some work on the
> definition to add what is meant by 'crude_oil' to what Mike has already
> provided which just defines 'mass fraction'.
>
>
> Cheers, Roy.
>
>
> Please note that I partially retired on 01/11/2015. I am now only working
> 7.5 hours a week and can only guarantee e-mail response on Wednesdays, my
> day in the office. All vocabulary queries should be sent to
> enquiries at bodc.ac.uk. Please also use this e-mail if your requirement is
> urgent.
>
>
> ------------------------------
> *From:* CF-metadata <cf-metadata-bounces at cgd.ucar.edu> on behalf of
> Jonathan Gregory <j.m.gregory at reading.ac.uk>
> *Sent:* 30 June 2016 17:06
> *To:* cf-metadata at cgd.ucar.edu
> *Subject:* Re: [CF-metadata] New standard name for
> mass_fraction_of_petroleum_in_sea_water
>
> Dear Mike
>
> I agree that petroleum_hydrocarbons is more specific and therefore
> preferable.
> Is it possible to omit "total", or does it have a specific meaning too and
> therefore convey some extra information? It would be good to be explicit if
> that is the case.
>
> Best wishes
>
> Jonathan
>
> ----- Forwarded message from mikegodino at yahoo.com -----
>
> > Date: Thu, 30 Jun 2016 15:57:35 +0000
> > From: mikegodino at yahoo.com
> > To: "Lowry, Roy K." <rkl at bodc.ac.uk>, Ute Br?nner <
> Ute.Broenner at sintef.no>,
> > "'cf-metadata at cgd.ucar.edu'" <cf-metadata at cgd.ucar.edu>
> > CC: Petter R?nningen <Petter.Ronningen at sintef.no>, J?rgen Skancke
> > <Jorgen.Skancke at sintef.no>, Tor Nordam <Tor.Nordam at sintef.no>, CJ
> > Beegle-Krause <CJ.Beegle-Krause at sintef.no>
> > Subject: Re: [CF-metadata] New standard name for
> > mass_fraction_of_petroleum_in_sea_water
> >
> > Dear Ute and Roy,
> > Thank you for your careful consideration and deliberation on my
> proposal. I would be satisfied by replacing "petroleum" in my original
> suggestion with either Ute's suggestion of "contaminant" or Roy's
> suggestion of "total_petroleum_hydrocarbons", although I find the latter a
> little more specific, particularly if one were to envision a situation in
> which intentionally released dispersants were being tracked at the same
> time and also categorized as "contaminants".
> > As to the question of mass concentration vs. mass fraction, I am trying
> to represent the measurements of the SeaOWL UV-A sensor (
> http://wetlabs.com/SeaOWL), which appears to be calibrated in units of
> ppm -- and hence mass fraction seems appropriate. The model that will
> assimilate these measurements is under active development, and may likely
> generate a mass concentration value. So perhaps there ought to be
> both mass concentration AND mass fraction standard names.
> <http://wetlabs.com/SeaOWL>
> SeaOWL UV-A? (Sea Oil-in-Water? Locator) | WET Labs
> <http://wetlabs.com/SeaOWL>
> wetlabs.com
> Sea-Bird Scientific introduces SeaOWL UV-ATM, a new in-situ oil-in-water
> sensor. Based-upon the highly successful WET Labs ECO sensor, Sea-Bird
> Scientific has ...
>
>
> > Thank you,Mike Godin
> > #yiv0904837381 #yiv0904837381 -- _filtered #yiv0904837381
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>
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