[Seavox] A question of principle on instruments

[John Graybeal]

In previous lives I have relied on the manufacturer model number as the authority on instrument 'types'.  It looks like L22 follows the same principal.

I strongly discourage differentiating instruments based on differences of application after manufacture, which this appears to be.  Model number is almost always appropriate, unless differences can be clearly identified as uniquely pertaining to a subclass of instruments with common, persistent characteristics. Because for a reusable vocabulary like L22, it's important that entries be equally applicable for all users of the instrument.

(Further discussion: 

In the extreme case, an instrument with an operating system can support an arbitrary number of different interfaces, protocols, or firmware or software configurations. And any instrument can have an arbitrary number of corrections and calibrations processes defined 'out of band', for example in the literature. 

If these differences are a part of an instrument's user-configurable nature, or of externally run data processing algorithms, the manufacturer probably sells that as one instrument model.  But physically, every instance is the same model, with common core characteristics. So that should be just one entry in the P22 vocabulary.

But if the manufacturer has different entries in the catalog for each sold configuration, those can be considered different instrument types, which need to be tracked over time, if the configuration of the instrument is fundamentally changed.
)

John


On Nov 8, 2013, at 08:48, "Giuseppe M. R. Manzella" <giuseppe.manzella at enea.it> wrote:

> Dear Roy,
> 
> unfortunately there are many questions related to the use of XBTs.
> For sure it is important to specify the type (T4, T6, Deep Blue or 
> other).
> Not all are using the same fall equation for the calculation of the 
> depth, and there is a wide variety of coefficients of the fall rate 
> equation used even for the same type.
> 
> For a general review of accuary problems related to instruments I 
> suggest this paper 
> http://onlinelibrary.wiley.com/doi/10.1002/rog.20022/pdf
> For the problems related to XBT this is another paper: Gouretski, V. 
> and F. Reseghetti, 2010, On depth and temperature biases in 
> bathythermograph data: Development of a new correction scheme based on 
> analysis of a global ocean database. Deep-Sea Research I, Vol. 57(6), 
> pp. 812-834, doi:10.1016/j.dsr.2010.03.011, Gouretski, Reseghetti 
> depth and temperature corrections, updated corrections.
> 
> 
> I personally would not use Sippical Fall rate or IGOOS fall rate, but 
> provide the value of coefficients.
> 
> Ciao
> 
> Giuseppe
> 
> 
> il Fri, 8 Nov 2013 15:38:37 +0000
>  "Lowry, Roy K." <rkl at bodc.ac.uk> ha scritto:
>> Dear All,
>> 
>> An issue is arising with a request to add a set of additional XBT 
>> entries to the SeaVoX instrument vocabulary (L22).  In most cases, 
>> this includes two entries for certain physical types of XBT (e.g. 
>> Sippican T5) with the entries differentiated by the fall-rate 
>> equation applied (Sippican or GOOS). I'm a little uneasy about this 
>> as to me it could be viewed as shoe-horning information that isn't 
>> actually instrument type into the instrument description. However, I 
>> am also aware of instruments that have multiple designations and all 
>> that's different between the variants is the firmware.
>> 
>> Anybody else have any views on this?
>> 
>> Cheers, Roy.
>> 
>> Please note that I now work part-time from Tuesday to Thursday. 
>> E-mail response on other days is possible but not guaranteed!
>> 
>> 
>> 
>> 
>> ________________________________
>> This message (and any attachments) is for the recipient only. NERC 
>> is subject to the Freedom of Information Act 2000 and the contents of 
>> this email and any reply you make may be disclosed by NERC unless it 
>> is exempt from release under the Act. Any material supplied to NERC 
>> may be stored in an electronic records management system.
> 
> \\
>>>   Giuseppe M.R. Manzella
>  //      ENEA CLIM
>          P.O. Box 225 - 19100 La Spezia
>          Italy
> 
> Representative in SCOR
> Operational Oceanography Coordinator
> tel +39 0187 9782 15  cell phone: 39 329 8313939
> fax +39 0187 9782 13
> e-mail: giuseppe.manzella at enea.it
> Access to Mediterranean Oceanographic Data
>      http://moon.santateresa.enea.it/
> Visit the European Environmental Data Bases Infrastructure
>      http://www.seadatanet.org/
> _______________________________________________
> Seavox mailing list
> Seavox at mailman.nerc-liv.ac.uk
> http://mailman.nerc-liv.ac.uk/mailman/listinfo/seavox

------------------------------------
John Graybeal
Sr. Data Manager, Metadata & Semantics

M +1 408 675-5545
skype: graybealski
Marinexplore
920 Stewart Drive
Sunnyvale 94085
California, USA
www.marinexplore.com