Hi Jon, Rachel, Dave and everyone else looking at GHG Vocabularies,

Thanks for all your comments.  I've updated the spread sheet (attached) to take into account your feedback.

First on the use of Dry Matter in the preferred units column.  I hadn't put DM in the preferred units for precisely the reason that Jon raised, that SI should not mix together information with units.  However all the GHG people who commented called for the inclusion of DM so I guess that means that this is a convention that your community has established so the proposed terms for the DTC archive that should reflect that.  

Dave raised issue of having two separate Nitrogen Oxide mass fluxes.  On reflection I agree that this makes no sense so I have combined the upward and downward fluxes into a single entity.

Rachel raised the fact that this list does not contain any terms relating to the Ammonia content in soils.  The terms listed here are intended to be examples to help when you, as a community, begin to define your own terms.  So for instance a good thing to think about would be:  can we reuse the units for Nitrate ions (g N kg-1 DM) for measurements of Ammonia?  

For things that are "unit of measure" I've removed the content in the preferred units box, that was confusing. 

The DTC archive allows us to specify equivalent units, so for instance g N kg-1 DM might have equivalent units of g N kg-1, the latter being the SI units related to this unit of measure.  In this example g N kg-1 DM would be the preferred unit for GHG platform terms. 

Finally, Ag has suggested that we do away with SI shorthand for units in our preferred units column and simply write the units long hand as they appear in the Identifier column.  I'm not sure that is a good idea because the preferred units are something that can be used as a check for what should be used in the headers of your data spread sheets.  But what do you think?


Best,
Charlotte 




________________________________________
From: Discussion list for Agricultural Greenhouse Gas Project CV [[log in to unmask]] on behalf of Jon Moorby [jxm] [[log in to unmask]]
Sent: 07 May 2013 15:40
To: [log in to unmask]
Subject: Re: GHG Platform vocabulary management update

Dear all,

I think we need careful consideration of the 'preferred units' column contents.

To my mind some of these are misleading.  Getting the units of measure for a particular number is clearly critical,  and it's not clear to me, even after reading the full definitions in the attached Excel sheet, what numbers associated with some IDs would mean.

E.g. row 10, nitrate ion mass concentration in soil.  I don't follow the definition - does this mean the concentration of nitrate ions (as nitrate) per unit of soil (wet weight or dry weight?), does it mean nitrate-N (i.e. nitrogen in the form of nitrate), or does it mean nitrate (or nitrate-N?) expressed as a proportion of total N concentration in the soil?  The units associated with this doesn't help work out which it is.

Another example is row 17, dry matter energy content [as an aside, this is wrong - it should be 'energy density' because 'energy' is not a nutrient, but is yielded from various nutrients/components].  The definition mentions mass dry matter, but the units don't include is.  This is critical - water in a sample yields no energy.  Units should be 'MJ kg-1 DM'.

Similarly row 19, water soluble carbohydrates, expressed per kg DM - units should be 'g kg-1 DM'.

Although under strict SI unit use 'information and units shouldn't be mixed', under practical conditions such as this I think that the less ambiguous we can make the unit notation the better.

On thought - the column is labelled 'preferred units'.  Does this mean that there are options of 'non-preferred' units too?

Jon

-----Original Message-----
From: Discussion list for Agricultural Greenhouse Gas Project CV [mailto:[log in to unmask]] On Behalf Of Charlotte Pascoe
Sent: 07 May 2013 09:37
To: [log in to unmask]
Subject: GHG Platform vocabulary management update

Dear green house gas people.

We've updated the example table of GHGP vocabulary terms and definitions and we would like you to review it.

Updating the vocabulary table is the first step in the transition of GHGP vocabulary management to the DTC Archive.
http://dtcarchive.org/vocabulary
You will notice that the new vocabulary terms in the attached spreadsheet are easier to read, for instance "ghgp-cv:chem:no3-n_mass_concentration_in_soil"  becomes "Nitrate ion mass concentration in soil".
However, making substantial changes means it is all the more important that the vocabulary update gets checked over by the community before we submit these terms to the DTC Archive.

We will submit these vocabulary terms to the archive on Friday 20th May, so please get your feedback to us before this date.

thanks in advance,
Charlotte

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