All ocean modelers report pH at in situ conditions. Some ocean observers report
pH corrected to 25°C, but when doing so they often call that pH25. Many ocean
observationalists report in situ pH, for example from data collected on buoys or
ARGO floats equiped with pH sensors.
Would it make sense to define pH25 as another CF variable in addition to the
current pH variable (in situ pH)? These variables may be considered as different
as in situ temperature and potential temperature.
regards,
Jim
On Thu, 8 Jun 2017, Lowry, Roy K. wrote:
Hi John,
Totally agree with you about the confidence level and what people SHOULD be
doing.
However, I am uncomfortable with CF becoming a tool to force those who have
quoted at standard conditions and
used the existing Standard Name rework their data. However, should a formal
approach from a
recognised authority in the carbonate chemistry community be made to CF then my
comfort level might rise
somewhat. Then it is they who is forcing the change, not CF.
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
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_____________________________________________________________________________________________________________
From: CF-metadata <[email protected]> on behalf of John Dunne -
NOAA Federal
<[email protected]>
Sent: 08 June 2017 18:58
To: Matthias Tuma
Cc: [email protected]
Subject: Re: [CF-metadata] Sea water pH values: at standard or in-situ
conditions?
Hi Matthias,
I'm going to have to go with in-situ, unless someone can correct me otherwise.
I'm 86.33% confident,
however. I have been looking at Jim Orr's documentation
(http://www.geosci-model-dev-discuss.net/gmd-2016-155/gmd-2016-155.pdf), and it
cites:
Biogeochemical protocols and diagnostics for the CMIP6 ...
www.geosci-model-dev-discuss.net
Biogeochemical protocols and diagnostics for the CMIP6 Ocean Model
Intercomparison Project (OMIP) James C.
Orr 1, Raymond G. Najjar 2, Olivier Aumont 3, Laurent Bopp ...
Dickson, A. G., Sabine, C. L., and Christian, J. R.: Guide to best practices
for ocean CO2 measurements, ,
PICES Special Publication 3, 191
pp., http://aquaticcommons.org/1443/, 2007.
[Guide_all_in_one.pdf]
Guide to best practices for ocean CO2 measurements ...
aquaticcommons.org
Item Type: Monograph or Serial Issue Title: Guide to best practices for ocean
CO2 measurements: Personal
Creator/Author:
which gives the calculations for pH on the total scale in SOP6a and SOP6b as a
function of insitu T as a
variable. Also, I would argue from an environmental science perspective that
we *should* be posting the
insitu variable.
Hope that helps! John
On Thu, Jun 8, 2017 at 5:56 AM, Matthias Tuma <[email protected]> wrote:
Hello all,
we had a question come up for the "sea_water_ph_reported_on_total_scale"
standard name: it
appears that for some communities, in particular on the measurement side,
pH would regularly be
reported only after first having converted to its equivalent at standard
conditions (25C, 0dbar).
In other communities, pH would most regularly be reported at in-situ
conditions (temperature and
pressure at actual measurement spot).
While we assume that the CF conventions would implicitly assume values to
be reported at in-situ
conditions (i.e., the latter variant), my two questions are:
1) whether someone can confirm this, to be 100% certain?, and
2) whether adding a few according clarifying words to the description
would be seen as useful?
Thanks and best,
Matthias
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