Difference between revisions of "Talk:Air Quality/Chemistry Naming Conventions"

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Go to [[Agreed_Items_Air_Quality/Chemistry_Naming_Convention|Agreed Items of Discussion on CF Naming Extensions - General ]].
 
Go to [[Agreed_Items_Air_Quality/Chemistry_Naming_Convention|Agreed Items of Discussion on CF Naming Extensions - General ]].
  
====CTextor: CF Naming Extensions====
 
I am in charge to organise the definition of new names for the CF convention, both as an outcome of our Ispra HTAP meeting  as well as by the EU-project GEMS. Do you have any information on what the status of naming conventions for aerosol&chemicals is? I have recently sent an email to Jonathan Gregory and Bryan Lawrence (see below). [[User:ChristianeTextor |ChristianeTextor ]] 19:26, 10 May 2006 (EDT)
 
  
====......FDetener: ACCENT Photocomp and O3 RF====
+
=Martin Schultz playing the devil's advocate =
:I give you the link to the ACCENT Photocomp [http://www.accent-network.org/farcry_accent/index.cfm?objectid=7C85FF9F-BCDC-BAD1-A5B24AD8463A158A&navid=3F6B52D0-802E-71AA-A15D8BB7251B563A input/output requirements]. Also have a look at the O3 RF. I guess we should discriminate between:
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4.7.2007
 +
Hi,
  
:a) components (and derived components)
+
  very good! It is becoming more and more clear to me that a lot of systematic thinking already went into the CF standards (and certainly Jonathan deserves a lot of credit for this). Yet, I am still a bit sceptical whether this can really get acceptance by the large community if they need to adapt so thoroughly and get rid of many old habits and custom units. Microsoft also made ist fortune by challenging the customer with small changes at a time and sacrificing the perfect system for a better chance to drag the crowd along. Translated to our problem at present, I am still wondering if it wouldn't be better to define some non-udunits "interim standards" just to keep people happy. And if they swallow the first bite and implement CF in their models and tools, one can then in a few years time work on making the system more stringent. My concern is also related to the non-existance of suitable evaluation tools which will make good use of all th enice attributes and standard names. More and more I get the impression that we are trying to model too many semantic sophistication into the definitions, which makes it practically impossible to project onto a software code as the complexity of this code must be quite large from the start. Yet another concern is my experience with improper netcdf files. Every error that can be made will be made at some point, and if we rely too much on the meaning of attributes, we are certain to get garbage results quite soon. One can of course implement some checking for consistency etc., but I see it as highly improbably that one will be able to catch all errors, and the system is becoming complex enough that it will be difficult to diagnose an error and correct it. Just two simple examples of what can easily go wrong:
:b) fluxes (e.g. O3 deposition, strat-trop, chemical production, chemical destruction)
+
(1) a certain software tool requires the ordering of levels from top to bottom, and thus you need a small program to reverse the order of the hybrid coefficients and all model fields. Since you are under pressure to deliver results, you will not worry about the attributes, and immediately your "direction:up" will be wrong. The file is still a "good" file in the sense that the plotting software can read it and will always display the correct information for a chosen level. Yet, if you want to take advantage of the "direction" attribute, you will be mislead.
:c) state variables like temperature, pressure, (and derived) radiative forcing
+
(2) assume you have a set of files with accumulated deposition fluxes ("amount" according to the new proposal). For a multi-year average of monthly values, you could for example use ncea from the NCO tools. Hardly anyone will afterwards think about a necessary adaptation of the standard name or cell_methods field (and how would you write this? "mean_of_sum"? impossible for any plotting program to"understand this!).  
:d) model info lon-lat structure, etc. [[User:FrankDetener|FrankDetener]]
+
  OK: my message is: (a) try to keep it simple, (b) avoid redundancies, (c) differentiate between tags for autmated processing and tags for human information, (d) provide very clear guidelines as to when a file is CF compliant and which standards are mandatory and which are optional (perhaps one should think about multiple "compliance levels"? level 0 would be the bony basics, level 1 would fulfill a certain set of elements necessary for standard automated processing, level 2 would include all tags amenable for automated processing, and level 3 includes correct tags for human information.
====......JGregory: CF Development ====
 
:Now CF is quite widely used, it is recognised that more explicit arrangements are needed for governing its development and giving it status and permanence. The original authors and others have been discussing how to do this. Something should be in place before long.  
 
  
:As regards the development of standard names for chemistry and aerosol, I would suggest that the work done by Peter van Velthoven for  [http://www.knmi.nl/~velthove/PRISM/CF/guidelines_chemistry_1.4.htm PRISM] is a good starting point. A good deal of thought was invested in that. However, since not many chemical names have so far been added, as you remark, these guidelines are only proposals, not requirements. ([http://wiki.esipfed.org/index.php/Talk:Wiki_Workspace#CTextor:_ESIP_Wiki_as_Temp_Location *See response by CTextor])[[user:JonathanGregory|JonathanGregory]] 17:28, 17 May 2006 (EDT)
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Don't misunderstand me, please! I am very much interested in seeing this happen (else I wouldnt reply at all). I am only playing the devil's advocate here.
  
====......RHusar: Additional Naming Information====
+
Best regards,
:Christiane, thank you for your note on CF naming extensions. Your work will be a very important part of developing interoperability among projects, programs, agencies and countries. Given the formal consensus-based procedures and the broad acceptance of the CF conventions in the met/ocean communities, it is a very attractive model for creating an Air Chemistry extension to the existing Standard Names.
 
  
:In order to collect the information on this topic, we have set up this [[Air Quality/Chemistry Naming Conventions|wiki page]]. It lists the standard air chemistry names in the CF convention (as of April 7, 2006). It is evident that the current list is very limited and it clearly requires expansion to accommodate the needs of this HTAP/GEMS project as well as the needs for other air quality/chemistry-related names.
+
Martin
 
 
:I do not have a direct interaction with the CF naming custodians, however I gather from the website that there is a particular e-mail address where naming requests are submitted.  The wiki page on air quality/chemistry naming also contains links three additional standard name collections:
 
 
 
:* EPA Air Quality System (AQS)
 
:* Supersite Project Naming Standards
 
:* PRISM Project Naming Standards
 
 
 
:I hope that this information will be of use. Clearly this is a major and thankless undertaking since it is so hard to do it "right" for every one's satisfaction. In order to distribute labor we have set up the above wiki pages where interested work group participants can enter links as well as descriptions through the open wiki process. If you would prefer to maintain such an interactive web page as part of your GEMS project we would be more than happy to make our contributions to those pages.[[User:Rhusar|Rhusar]] 19:30, 10 May 2006 (EDT)
 

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Martin Schultz playing the devil's advocate[edit source | reply | new]

4.7.2007 Hi,

  very good! It is becoming more and more clear to me that a lot of systematic thinking already went into the CF standards (and certainly Jonathan deserves a lot of credit for this). Yet, I am still a bit sceptical whether this can really get acceptance by the large community if they need to adapt so thoroughly and get rid of many old habits and custom units. Microsoft also made ist fortune by challenging the customer with small changes at a time and sacrificing the perfect system for a better chance to drag the crowd along. Translated to our problem at present, I am still wondering if it wouldn't be better to define some non-udunits "interim standards" just to keep people happy. And if they swallow the first bite and implement CF in their models and tools, one can then in a few years time work on making the system more stringent. My concern is also related to the non-existance of suitable evaluation tools which will make good use of all th enice attributes and standard names. More and more I get the impression that we are trying to model too many semantic sophistication into the definitions, which makes it practically impossible to project onto a software code as the complexity of this code must be quite large from the start. Yet another concern is my experience with improper netcdf files. Every error that can be made will be made at some point, and if we rely too much on the meaning of attributes, we are certain to get garbage results quite soon. One can of course implement some checking for consistency etc., but I see it as highly improbably that one will be able to catch all errors, and the system is becoming complex enough that it will be difficult to diagnose an error and correct it. Just two simple examples of what can easily go wrong:

(1) a certain software tool requires the ordering of levels from top to bottom, and thus you need a small program to reverse the order of the hybrid coefficients and all model fields. Since you are under pressure to deliver results, you will not worry about the attributes, and immediately your "direction:up" will be wrong. The file is still a "good" file in the sense that the plotting software can read it and will always display the correct information for a chosen level. Yet, if you want to take advantage of the "direction" attribute, you will be mislead. (2) assume you have a set of files with accumulated deposition fluxes ("amount" according to the new proposal). For a multi-year average of monthly values, you could for example use ncea from the NCO tools. Hardly anyone will afterwards think about a necessary adaptation of the standard name or cell_methods field (and how would you write this? "mean_of_sum"? impossible for any plotting program to"understand this!).

  OK: my message is: (a) try to keep it simple, (b) avoid redundancies, (c) differentiate between tags for autmated processing and tags for human information, (d) provide very clear guidelines as to when a file is CF compliant and which standards are mandatory and which are optional (perhaps one should think about multiple "compliance levels"? level 0 would be the bony basics, level 1 would fulfill a certain set of elements necessary for standard automated processing, level 2 would include all tags amenable for automated processing, and level 3 includes correct tags for human information.

Don't misunderstand me, please! I am very much interested in seeing this happen (else I wouldnt reply at all). I am only playing the devil's advocate here.

Best regards,

Martin