Re: [CF-metadata] Putting the units in a CF standard name: area_fraction

Hi Steve, yes, but I was suggesting a change in the standard name ... you seemed to be suggesting not using it, which would leave variables without a standard name. regards, Martin From: Steven Emmerson Sent: 31 January 2019 18:27 To: Juckes, Martin

Re: [CF-metadata] Putting the units in a CF standard name: area_fraction

Martin, On Thu, Jan 31, 2019 at 9:32 AM Martin Juckes - UKRI STFC < martin.juc...@stfc.ac.uk> wrote: > In the interests of clarity, could you say why the option I've proposed is > not in your list? > I'm sorry. I thought you proposed not using the word "fraction", so that, for example,

Re: [CF-metadata] Putting the units in a CF standard name: area_fraction

Martin, I like your definition. While there is a case for renaming the standard name, it’s long-time use, validity, and the fact only sophisticated data managers use standard names (and most data users just look primarily at variable names) says to me we should keep the existing standard

[CF-metadata] CMIP6 Confusion regarding carbon flux units

Dear Martin, dear All, it is emerging that groups are making errors in implementing the carbon cycle data requests - especially regarding the units of carbon fluxes. The issue is confusion over whether to report kg of CARBON or kg of CO2. The intended correct answer is buried deep within

Re: [CF-metadata] CMIP6 Confusion regarding carbon flux units

Dear Chris, Martin, Roy, I am sorry to hear that confusion is occurring regarding the carbon flux names in C4MIP. I certainly take Chris's point that it would be very unfortunate if the data contain large errors due to misunderstanding of what the variables should contain. However, I do agree

Re: [CF-metadata] CMIP6 Confusion regarding carbon flux units

Dear all While I sympathise with the problem, I too think that we shouldn't include carbon in the units. In CF and the standard names we have always kept the meaning of the quantity out of the units. Clearly it's important for the data to be correct, but that applies to every- thing requested by

[CF-metadata] Putting the units in a CF standard name: area_fraction

Dear Martin I'd rather we retained "fraction" in the standard name, because it's always been there, it's used in other contexts in a consistent way, and there isn't anything actually incorrect with it, as you say. Could we instead add a note to the definitions pointing out that percent is

Re: [CF-metadata] CMIP6 Confusion regarding carbon flux units

Dear Chris, All, I think I should start by explaining some context for the benefit of those on this list that are not familiar with CMIP or the CMIP6 Data Request. Chris is leading an international science team (C4MIP) that is participating in the CMIP6 model

Re: [CF-metadata] CMIP6 Confusion regarding carbon flux units

Dear Chris, The embedding of semantics in units of measure is something I have fought against for decades, largely because software agent AI algorithms are unlikely to look for them there. Your suggestion is also something that would never get past the guardians of UDUNITS. However, I can

Re: [CF-metadata] Putting the units in a CF standard name: area_fraction

Hi Steve, In the interests of clarity, could you say why the option I've proposed is not in your list? I'm not convinced that adopting your choice 2. will promote common language among disciplines. It is a laudable aim, but I fell it would be better taking into account the way in which are

Re: [CF-metadata] Putting the units in a CF standard name: area_fraction

Dear Jonathan, we could certainly take that approach, though the definitions are not always accessible to people looking at the standard name, so they do not compensate for ambiguity in the name itself. The current text '"Area fraction" means the fraction of horizontal area.' could be

Re: [CF-metadata] Putting the units in a CF standard name: area_fraction

Hi. I understand that concern, but it has always been true that the units for a quantity identified by a standard name only has to be convertible using UDUNITS from the canonical units specified in the definition for that standard name. So percent is, by definition, valid for a quantity with

Re: [CF-metadata] Putting the units in a CF standard name: area_fraction

Martin, So, it would seem like the potential solutions to the problem you perceive are 1. Not use the standard name "fraction" in variable names to accommodate people who are confused when the values are given in percent; or 2. Use the standard name "fraction" and expect people to